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The most used tools by our community
The developer tools our community reaches for most. These utilities cover the everyday workflow — formatting JSON, decoding JWTs, generating UUIDs, encoding with Base64, and more. Each tool runs entirely in your browser, which means your data never leaves your device. Rankings reflect real usage across the platform, so this list shows you what other developers actually rely on.
Free online JSON formatter and validator with syntax highlighting and error line numbers. Use as default for beautify+validate+minify in one place; for two-file comparison use json-diff, for schema generation use json-schema-generator. Input: JSON ≤10MB. Returns formatted JSON or line-numbered error. 100% private.
Free online Base64 encoder and decoder with URL-safe mode. Use as default for text; for split encode-only/decode-only URLs use base64-encoder/base64-decoder (aliases), for image files use image-to-base64. Input: text ≤10MB. Returns Base64 string or decoded text + error location. Convert instantly in your browser.
Decode and inspect JWT header, payload and expiry locally. Debug tokens securely in browser.
Generate original mathematics practice questions across school, competitive-exam, university, and advanced levels. For students, teachers, and tutors.
Free online SQL formatter with indentation and keyword casing. Format queries privately in browser.
Free online URL encoder and decoder for query strings and components. Private client-side conversion.
Free UUID v4/v7 generator with bulk mode and JSON export. Cryptographically random, runs client-side.
Calculate BMI from height and weight. Use for health screening; for calories use bmr-tdee-calculator. Input: cm/kg. Returns BMI + category. 100% client-side, files never leave browser.
Create QR codes for URLs, Wi-Fi, vCards and text. Adjust size and error correction, download PNG/SVG.
Calculate exact age from birthdate. Use for years/months/days; for differences use date-calculator. Input: date. Returns age. 100% client-side, files never leave browser.
Merge multiple PDFs in order. Use when combining; for splitting use pdf-splitter. Input: PDFs ≤10MB. Returns merged PDF. 100% client-side, files never leave browser.
Compress JPEG, PNG, and WebP images in your browser. Reduce file size without visible quality loss.
Descriptive statistics for a list of numbers: mean, median, mode, range, variance, standard deviation.
Split PDF by pages or ranges. Use when extracting; for combining use pdf-merger. Input: PDF ≤10MB. Returns split PDFs. 100% client-side, files never leave browser.
Minify JS for production or beautify minified JS for debugging. Use for JS only; for JSON use json-formatter, for CSS use css-formatter. Input: JS text ≤10MB. Returns minified or beautified JS or syntax error. 100% client-side.
Generate secure passwords and passphrases with length and symbol controls. Uses Web Crypto API locally.
Scientific calculator with trig and logs. Use for advanced math; for datasets use statistics-calculator. Input: expression. Returns result. 100% client-side, files never leave browser.
Convert JSON arrays to CSV for spreadsheets. Paste JSON, pick a delimiter, and download the CSV instantly.
Computes EMI from principal, rate and tenure with full amortization. Use for any generic loan estimate; differs from auto-loan by generic terms vs vehicle fees and down payment. Returns EMI, total interest and schedule. 100% client-side.
College GPA on the 4.0 scale with per-course credits, including Honors/AP weighted GPA.
Convert JPG/PNG/WebP images to PDF. Use when archiving scans; for PDF to images use pdf-to-jpg. Input: images ≤10MB. Returns PDF. 100% client-side, files never leave browser.
Resize images by width/height or percent. Use when dimensions must change; for smaller files use image-compressor. Input: image ≤10MB. Returns resized PNG/JPEG/WebP. 100% client-side, files never leave browser.
Format and validate HTML with indentation and error reporting. Use as default HTML tool; for minifying production HTML use html-minifier, for converting HTML to Markdown use html-to-markdown. Input: HTML ≤10MB. Returns formatted HTML or validation errors. 100% client-side.
Paste CSV and get JSON. Handles headers, delimiters, and spreadsheet exports — all locally.
Crop images with aspect presets and free select. Use when trimming; for scaling use image-resizer. Input: image ≤10MB. Returns cropped PNG/JPEG. 100% client-side, files never leave browser.
Projects lump-sum growth from principal, rate, years and compounding frequency. Use when forecasting a one-time deposit; differs from sip-calculator by single deposit vs monthly contributions. Returns maturity value, interest and schedule. 100% client-side.
Converts amounts across currencies using live exchange rates. Use for travel or invoicing FX checks; differs from unit-converter by money vs physical units. Returns converted amount and rate. Server fetches public rates; inputs stay local.
Calculate the exact number of days, weeks, months, and years between two dates. Handles leap years and varying month lengths correctly.
Add, subtract, multiply, and divide fractions with exact rational arithmetic — no floating-point drift. Simplifies automatically.
Generate MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashes for text. Copy or compare instantly.
Generate TypeScript interfaces from JSON with optional readonly and export. Use for TS types; for Go use json-to-go, for generic code use json-to-code. Input: JSON ≤10MB. Returns .ts interfaces or JSON error. 100% client-side.
Add text or logo watermark to images. Use for branding; for cropping use image-cropper. Input: image ≤10MB. Returns watermarked image. 100% client-side, files never leave browser.
Count words, characters, and sentences. Get reading time and Flesch score as you type.
Projects SIP wealth from monthly amount, expected return, years and timing. Use when planning recurring fund contributions; differs from compound-interest-calculator by monthly deposits vs lump sum. Returns maturity value, invested total and chart. 100% client-side.
Find the score you need on the remaining coursework to hit your target final grade.
Convert AWG gauge to mm and diameter. Use for sizing wire; for drop use voltage-drop-calculator. Input: AWG number. Returns specs. 100% client-side, files never leave browser.
Export PDF pages as JPG/PNG images. Use when extracting images; for images to PDF use image-to-pdf. Input: PDF ≤10MB. Returns JPGs. 100% client-side, files never leave browser.
Find and replace text with literal, regex, and case-insensitive modes. Shows replacement count.
Convert Unix timestamps to readable dates and back. Supports timezones and multiple formats.
Format or minify CSS with indentation control. Use as default CSS tool handling both directions; css-minifier URL is a noindex alias. Input: CSS ≤10MB. Returns formatted or minified CSS. 100% client-side.
Convert Markdown to HTML with live preview. Use for publishing Markdown; for editing with preview use markdown-editor, for reverse direction use html-to-markdown. Input: Markdown ≤10MB. Returns HTML. 100% client-side.
Create signed JWTs (HS256/RS256) from header+payload locally. Use when creating test tokens; for inspecting existing tokens use jwt-decoder, for Base64 parts use base64. Input: JSON header/payload + secret. Returns JWT string. 100% client-side.
Plans home-loan payoff from balance, rate, term and extra payments. Use when weighing extra payments or refinance; differs from loan-emi-calculator by escrow, taxes and payoff focus. Returns payoff date, interest saved and schedule. 100% client-side.
Estimates income tax from income, deductions and filing regime. Use when comparing old vs new regime liability; differs from capital-gains-tax by salary income vs asset-sale gains. Returns tax payable, effective rate and slab split. 100% client-side.
Basal metabolic rate (Mifflin-St Jeor) and daily calorie needs by activity level, metric or imperial.
Calculate percentage increase, decrease, difference, and relative change between two values.
Solve voltage, current, resistance, and power from any two knowns (V=IR, P=VI).
Reduce PDF file size. Use when sharing; for images use image-compressor. Input: PDF ≤10MB. Returns compressed PDF. 100% client-side, files never leave browser.
Generate code types from JSON. Use for boilerplate; for TS only use json-to-typescript, for Go use json-to-go. Input: JSON ≤10MB. Returns code. 100% client-side, files never leave browser.
Test and debug regular expressions with live matching and capture groups. Paste pattern and sample text.
Analyze text for word count, readability, and language stats. Paste and get instant insights.
Convert between HEX, RGB, HSL, HSV, and CMYK. Pick a color and copy any format.
Preview rendered Markdown without editing. Use for quick read-only preview; for editing use markdown-editor, for HTML output copy use markdown-to-html. Input: Markdown ≤10MB. Returns rendered HTML preview. 100% client-side.
Computes margins from revenue and cost or price inputs. Use when pricing products; differs from roi-calculator by per-sale margin and markup vs investment return. Returns gross margin %, net margin and markup %. 100% client-side.
Count working days (Mon–Fri) between two dates, or add/subtract business days. Leap-year and month-length correct.
Calculate sale price after discount. Use for percent off; for change percent use percentage-change-calculator. Input: price + percent. Returns final price. 100% client-side, files never leave browser.
Pick colors and copy HEX/RGB/HSL. Use for palette building; for image sampling use color-eyedropper. Input: color selection. Returns color codes. 100% client-side, files never leave browser.
Compare two JSON documents and highlight added, removed, and changed keys with line-level diff. Use when comparing API responses or configs; for single-document formatting use json-formatter, for validation errors use json-validator. Input: two JSON texts ≤10MB. Returns highlighted diff. 100% client-side.
Calculate voltage drop over wire runs. Use for wiring; for sizing use wire-gauge-calculator. Input: length/load/AWG. Returns drop percent. 100% client-side, files never leave browser.
Convert images to Base64 encoded strings online for free. Use for image files only; for text use base64. Input: image file ≤10MB. Returns Base64 data URI for HTML/CSS/JS. Generate Base64 data URIs for embedding images directly in HTML, CSS, and JavaScript code.
Pretty-print minified JSON with 2-space indentation and syntax highlighting. Use when readable JSON is needed; for minifying use json-minifier, for full validate+format workflow use json-formatter. Input: JSON text ≤10MB. Returns formatted JSON or line-numbered error. 100% client-side.
Generate fake names, emails, and addresses for testing. Use for mock data. Input: options + count. Returns CSV/JSON rows. 100% client-side.
Convert JSON to YAML for configs. Use for JSON input; for YAML validation use yaml-formatter, for TOML cross-format use toml-converter. Input: JSON ≤10MB. Returns YAML or JSON error. 100% client-side.
Infer JSON Schema from sample JSON for validation. Use when authoring schemas; for validating instances use json-validator. Input: JSON ≤10MB. Returns JSON Schema draft. 100% client-side.
Score password entropy, crack time, and improvement tips. Use for auditing; for creating passwords use password-generator. Input: password text (never stored). Returns score + feedback. 100% client-side.
Check foreground/background contrast against WCAG 2.2 AA/AAA with ratio and pass/fail. Use for accessibility audits; for format conversion use color-converter, for picking use color-picker. Input: two colors. Returns ratio + grade. 100% client-side.
Calculate network, broadcast, and host range from CIDR. Use for subnet math; for geo lookup use ip-lookup. Input: IP/CIDR. Returns network details. 100% client-side.
Add or subtract days and diff dates. Use for durations; for workdays use business-days-calculator. Input: dates. Returns difference. 100% client-side, files never leave browser.
Measures total return from amount invested and amount returned. Use for single-holding profit checks; differs from cagr-calculator by overall % vs annualized rate. Returns ROI %, net gain and cost breakdown. 100% client-side.
Projects retirement corpus from age, savings, contributions and expected return. Use when planning nest egg and withdrawals; differs from savings-goal-calculator by lifelong horizon vs dated target. Returns corpus, shortfall and projection. 100% client-side.
Estimate body-fat percentage from measurements using the US Navy circumference method (DoDI 1308.3).
Create animated GIF from images. Use when animating frames; for collages use image-collage. Input: images ≤10MB. Returns GIF. 100% client-side, files never leave browser.
Rotate images 90, 180, or 270 degrees and flip them horizontally or vertically. Preview and download — files never leave your browser
Validate JSON syntax and report errors with line numbers without reformatting. Use when only correctness matters; for auto-fix and formatting use json-formatter. Input: JSON text ≤10MB. Returns valid/invalid + error location. 100% client-side.
Escape/unescape JS strings. Use for code literals; for JSON strings use json-escaper. Input: text ≤10MB. Returns escaped text. 100% client-side.
Format and validate XML with indentation and well-formedness checks. Use for XML; for JSON use json-formatter, for XML to JSON conversion use xml-to-json. Input: XML ≤10MB. Returns formatted XML or line-numbered error. 100% client-side.
Convert HTML to Markdown for CMS exports and docs. Use for HTML input only; for Markdown to HTML use markdown-to-html. Input: HTML ≤10MB. Returns Markdown. 100% client-side.
Converts length, weight, volume, area and speed between metric and imperial units. Use for everyday measurements; differs from currency-converter by physical units vs live money rates. Returns value with formula. 100% client-side.
Generate time-based OTP codes from authenticator secret. Use for 2FA testing; for random tokens use token-generator. Input: Base32 secret. Returns 6-digit code + QR. 100% client-side.
Hash passwords with bcrypt (cost-configurable) and verify. Use for password storage; for fast checksums use hash-generator, for keyed MACs use hmac-generator. Input: password text. Returns bcrypt hash. 100% client-side.
Read EXIF metadata (camera, GPS, settings). Use when inspecting photos; for moving EXIF use exif-transfer. Input: JPEG/TIFF ≤10MB. Returns metadata table. 100% client-side, files never leave browser.
Find JSONPath expressions by clicking any key. Use when querying APIs; for formatting use json-formatter. Input: JSON ≤10MB. Returns matching paths and values. 100% client-side.
Search and copy emoji with keywords. Use when inserting emoji; for ASCII art use ascii-art. Input: search text. Returns emoji to copy. 100% client-side.
Search common git commands with examples. Use as quick reference; for regex help use regex-memo. Input: search text. Returns command snippets. 100% client-side.
Measures smoothed annual growth from start value, end value and years. Use when comparing investments over time; differs from roi-calculator by annualized rate vs total return. Returns CAGR %, total growth and yearly table. 100% client-side.
Plans multi-debt payoff from balances, APRs, minimums and monthly budget. Use when comparing snowball vs avalanche; differs from credit-card-payoff by multiple debts vs single card. Returns debt-free date, interest total and order. 100% client-side.
Estimates car payments from price, down payment, trade-in, rate and term. Use when shopping vehicle financing; differs from loan-emi-calculator by auto fees vs generic loan. Returns monthly payment, total cost and schedule. 100% client-side.
Compute mean, median and stddev. Use for datasets; for single expressions use scientific-calculator. Input: numbers ≤10MB. Returns stats. 100% client-side, files never leave browser.
Solve ax² + bx + c = 0, including complex conjugate roots.
Combine images into a grid collage. Use for side-by-side; for animation use gif-maker. Input: images ≤10MB. Returns collage PNG. 100% client-side, files never leave browser.
Convert images between PNG, JPEG, and WebP with a quality slider. See the final size before you download — 100% local
Escape or unescape JSON strings. Use when embedding JSON; for formatting use json-formatter. Input: JSON ≤10MB. Returns escaped string. 100% client-side, files never leave browser.
Remove duplicate lines from text while keeping first-seen order. Case and trim options.
Encode/decode HTML entities (& < >). Use for HTML text; for URLs use url-encoder. Input: text ≤10MB. Returns encoded/decoded text. 100% client-side.
Format and validate YAML with syntax checks. Use for YAML editing; for JSON to YAML conversion use json-to-yaml, for TOML/YAML/JSON cross-conversion use toml-converter. Input: YAML ≤10MB. Returns formatted YAML or error. 100% client-side.
Compress JSON by stripping whitespace for smallest payload. Use when preparing production payloads; for readable output use json-formatter or json-beautifier. Input: JSON text ≤10MB. Returns minified JSON or line-numbered error. 100% client-side.
Generate lorem ipsum placeholder text. Use for mock layouts. Input: paragraphs/sentences count. Returns dummy text. 100% client-side.
Convert XML to JSON preserving attributes and nesting. Use for XML input only; for reverse use json-to-xml. Input: XML ≤10MB. Returns JSON or XML parse error. 100% client-side.
Compute HMAC-SHA256/SHA512 for message authentication. Use for webhook signatures; for plain hashes use hash-generator. Input: message + secret key. Returns hex HMAC. 100% client-side.
Encrypt/decrypt text with AES password. Use for secrets. Input: text + password ≤10MB. Returns ciphertext/plaintext. 100% client-side.
Generate favicons (16/32/180 PNG + ICO) from one image. Use for site icons; for compression use image-compressor. Input: image ≤10MB. Returns favicon set + HTML. 100% client-side, files never leave browser.
Split any URL into protocol, host, path, and query params. Use when inspecting URLs; for encoding query strings use url-encoder. Input: URL text. Returns component table. 100% client-side.
Calculate percentages, increase, and tips. Use for quick percent math; for change between values use percentage-change-calculator. Input: numbers. Returns percent result. 100% client-side.
Plans savings from target amount, deadline, current savings and rate. Use when hitting a dated goal; differs from retirement-savings by short-term target vs lifelong corpus. Returns monthly amount, schedule and shortfall. 100% client-side.
Plans single-card payoff from balance, APR and monthly payment. Use when clearing one card fastest; differs from debt-payoff by single card vs multi-debt snowball/avalanche. Returns months to payoff, interest cost and schedule. 100% client-side.
Estimates education-loan payments from principal, rate, term and grace options. Use when comparing repayment plans; differs from auto-loan by study terms vs vehicle purchase. Returns monthly payment, interest and schedule. 100% client-side.
Ideal body weight by height using four published formulas (Devine, Robinson, Miller, Hamwi) side by side.
Find the day of week for any date. Shows weekday name, day-of-year, and leap year status. Uses proleptic Gregorian calendar.
Compute nCr (combinations) and nPr (permutations) with exact integer arithmetic. Supports large n via logarithms.
Estimate reading and speaking time from text with adjustable words-per-minute rates. Includes word, character, sentence, and paragraph counts.
Convert text to hex and back. Use for hex encoding; for hashes use hash-generator. Input: text ≤10MB. Returns hex string or decoded text. 100% client-side.
Generate SEO/social meta tags (Open Graph/Twitter). Use for new pages. Input: title/description/URL. Returns HTML tags. 100% client-side.
Convert JSON to XML with root element control. Use for JSON input only; for reverse use xml-to-json, for JSON to YAML use json-to-yaml. Input: JSON ≤10MB. Returns XML or line-numbered JSON error. 100% client-side.
Convert text between camelCase, PascalCase, snake_case, kebab-case and UPPER. Use for code naming; for URL slugs use slug-generator. Input: text ≤10MB. Returns converted cases. 100% client-side.
Extract HTML tables to JSON arrays for scraping. Use for <table> input only; for CSV to JSON use csv-to-json. Input: HTML with tables ≤10MB. Returns JSON array or NO_TABLE_FOUND error. 100% client-side.
Decode SSL certificates (subject/expiry/chain). Use for debugging certs. Input: PEM text ≤10MB. Returns parsed fields. 100% client-side.
Generate sortable ULIDs (time-ordered IDs). Use when ordering matters; for random UUIDs use uuid-generator, for tokens use token-generator. Input: count option. Returns ULID strings. 100% client-side.
Minify SVG by stripping metadata and whitespace. Use for smaller vectors; for raster use image-compressor. Input: SVG ≤10MB. Returns optimized SVG. 100% client-side, files never leave browser.
Parse raw HTTP headers into readable name-value pairs. Use when debugging responses; for URL parts use url-parser. Input: header text ≤10MB. Returns table of headers. 100% client-side.
Evaluate math expressions with functions safely. Use for quick calc; for scientific history use scientific-calculator. Input: expression text. Returns numeric result. 100% client-side.
Look up HTTP status code meanings and fixes. Use as quick reference; for header debug use http-header-parser. Input: code or search. Returns description. 100% client-side.
Estimates tax from buy price, sell price, holding period and asset type. Use when selling stocks, property or funds; differs from income-tax-calculator by asset gains vs salary income. Returns taxable gain, tax due and STCG/LTCG split. 100% client-side.
Estimates affordable home price from income, debts, down payment and rate. Use before house hunting; differs from mortgage-payoff by max budget vs existing-loan payoff. Returns affordable price, monthly payment and DTI check. 100% client-side.
Splits restaurant bills from subtotal, tip %, tax and party size. Use when dining out or splitting; differs from vat-gst by gratuity split vs tax-inclusive pricing. Returns tip amount, total and per-person share. 100% client-side.
Calculate z-score (standard score) from raw value, mean, and standard deviation. Supports p-value lookup.
Create 1D barcodes (Code128/EAN/UPC). Use for products; for 2D codes use qr-generator. Input: text/numbers. Returns PNG/SVG. 100% client-side.
Generate QR for WiFi join (SSID/auth/password). Use for WiFi sharing only; for URLs/text use qr-generator. Input: SSID + security + password. Returns QR PNG/SVG. 100% client-side.
Generate Go structs with json tags from JSON. Use for Go only; for TypeScript use json-to-typescript. Input: JSON ≤10MB. Returns Go code or JSON error. 100% client-side.
Compute MD5/SHA-256/SHA-512 checksums for files to verify integrity. Use for files; for text strings use hash-generator. Input: file ≤10MB. Returns hex digests. 100% client-side, files never uploaded.
Generate RSA key pairs locally. Use for SSH/TLS testing. Input: key-size option. Returns PEM public/private keys. 100% client-side.
Convert SVG to CSS background data URI. Use for inline icons; for image files use image-to-base64. Input: SVG ≤10MB. Returns CSS url(). 100% client-side, files never leave browser.
Parse user-agent strings into browser, OS, and device. Use when debugging traffic; for live device data use device-information. Input: UA string. Returns parsed fields. 100% client-side.
Compares renting vs buying from rent, price, down payment, rate and horizon. Use when deciding to buy or rent; differs from home-affordability by side-by-side costs vs max budget. Returns cheaper option and break-even year. 100% client-side.
Discount a future lump sum or stream of payments back to today. Result stays in your browser
Simplify ratios, split a total in a given ratio, and solve proportions a:b = c:x.
Total resistance for any list of resistors in series or parallel.
Embed raster images as SVG. Use when needing SVG wrappers; for optimizing vectors use svg-optimizer. Input: image ≤10MB. Returns SVG. 100% client-side, files never leave browser.
Calculate simplified and decimal aspect ratios from width and height, and scale dimensions while preserving the ratio
Normalize line breaks to LF (Unix/Mac) or CRLF (Windows), or remove them entirely.
Convert text to binary and back. Use for binary strings; for other bases use base-converter. Input: text ≤10MB. Returns 0/1 string or decoded text. 100% client-side.
Convert docker run commands to Docker Compose YAML files online for free. Simplify container orchestration with this easy migration tool.
Edit Markdown with side-by-side live HTML preview and export. Use as default authoring tool; for conversion-only without editing use markdown-to-html. Input: Markdown ≤10MB. Returns edited Markdown + HTML preview. 100% client-side.
Converts Celsius, Fahrenheit, Kelvin and Rankine instantly. Use for weather, cooking or science; differs from unit-converter by temperature scales vs length/weight. Returns all-scale equivalents. 100% client-side.
Look up geolocation and ISP for any IP address. Use for geo data; for subnet math use ip-calculator. Input: IPv4/IPv6. Returns location and ASN. 100% client-side.
Visual side-by-side diff for two texts with char-level highlights. Use as default diff tool; for similarity score use string-comparison, for JSON use json-diff. Input: two texts ≤10MB. Returns visual diff. 100% client-side.
Converts numbers between binary, octal, decimal and hex bases. Use when debugging encodings or flags; differs from roman-numeral-converter by positional bases vs Roman symbols. Returns all-base equivalents. 100% client-side.
Generate BIP39 seed phrases for wallets. Use for testing only. Input: word-count option. Returns mnemonic words. 100% client-side.
Generate placeholder images by size and text. Use for mockups; for editing photos use image-resizer. Input: dimensions + options. Returns PNG download. 100% client-side, files never leave browser.
Compare two texts line-by-line with inline changes. Legacy alias of text-diff-visual; prefer text-diff-visual or string-comparison for similarity %. Input: two texts ≤10MB. Returns diff. 100% client-side.
Convert text to URL-friendly slug. Noindex alias of slug-generator; prefer slug-generator for full workflow. Input: text ≤10MB. Returns slug. 100% client-side.
Calculate IPv4 subnets, masks, and host counts. Use for IPv4 planning; for IPv6 use ipv6-calculator. Input: CIDR or mask. Returns subnet table. 100% client-side.
Quick regex syntax cheatsheet with examples. Use when looking up syntax; for live testing use regex-tester. Input: search text. Returns pattern snippets. 100% client-side.
Computes DTI from gross monthly income and debt payments. Use when checking loan eligibility; differs from home-affordability by ratio check vs max house budget. Returns DTI %, front/back-end split and risk band. 100% client-side.
Projects FD maturity from principal, rate, tenure and payout frequency. Use for one-time term deposits; differs from recurring-deposit by lump sum vs monthly deposits. Returns maturity value, interest earned and growth table. 100% client-side.
Full monthly amortization schedule for a fixed-rate loan: EMI, per-payment principal/interest split, and running balance. Downloadable as CSV
Find the ISO 8601 week number, weekday, day-of-year, and leap-year status for any date.
Greatest common divisor and least common multiple of two or more numbers via Euclid's algorithm.
Minify HTML for production by stripping whitespace. Use for production builds; for readable HTML use html-formatter. Input: HTML ≤10MB. Returns minified HTML. 100% client-side.
View and navigate YAML with collapsible tree and validation. Use for read-only inspection; for editing/validation use yaml-formatter. Input: YAML ≤10MB. Returns tree view or error. 100% client-side.
Turn text into ASCII art banners. Use for headers and fun. Input: text ≤10MB. Returns ASCII art to copy. 100% client-side.
Generate random secure tokens. Use for secrets; for IDs use uuid-generator/ulid-generator. Input: length options. Returns token strings. 100% client-side.
Build vCard contacts to share or QR. Use for business cards. Input: name/phone/email. Returns .vcf download. 100% client-side.
Reformats delimited lists between commas, lines, JSON, SQL and bullets. Use when cleaning pasted lists; differs from case-converter by delimiters and structure vs letter casing. Returns list with dedupe options. 100% client-side.
Build Content-Security-Policy headers. Use for XSS hardening. Input: directive options. Returns policy string. 100% client-side.
Parse phone numbers to E.164 and region. Use for validation. Input: number + country. Returns formats + validity. 100% client-side.
Sort lines alphabetically and remove duplicates. Use when cleaning lists; for comparing two texts use text-diff-visual. Input: text lines ≤10MB. Returns sorted unique lines. 100% client-side.
Look up DNS records for any domain. Use when checking DNS; for IP geo use ip-lookup. Input: domain name. Returns A, MX, TXT records. 100% client-side.
Generate Basic Auth headers from username and password. Use when testing APIs; for JWTs use jwt-generator. Input: credentials text. Returns Authorization header. 100% client-side.
Convert IPv4 between dotted, hex, integer, and binary. Use for format shifts; for subnet math use ipv4-subnet-calculator. Input: IPv4 address. Returns all formats. 100% client-side.
Format dates into ISO, RFC, and locale strings. Use for display formats; for Unix epochs use timestamp-converter. Input: date text. Returns formatted dates. 100% client-side.
Calculate IPv6 subnets, expansion, and compression. Use for IPv6 planning; for IPv4 use ipv4-subnet-calculator. Input: IPv6/CIDR. Returns subnet details. 100% client-side.
Finds break-even from fixed costs, price and variable cost per unit. Use when pricing a venture; differs from profit-margin-calculator by units to cover costs vs margin %. Returns break-even units, revenue and safety margin. 100% client-side.
Projects RD maturity from monthly deposit, rate and tenure. Use for monthly fixed-income saving; differs from fixed-deposit by recurring deposits vs one-time lump sum. Returns maturity value, deposits total and interest. 100% client-side.
Adds or strips VAT/GST from net or gross amounts at any rate. Use at checkout or invoicing; differs from tip-calculator by tax compliance vs gratuity. Returns net, tax and gross amounts with rate breakdown. 100% client-side.
Net present value of a series of cash flows at a discount rate. Result stays in your browser
Internal rate of return for a series of periodic cash flows. Result stays in your browser
Encode and decode geohashes. Use when sharing locations; for timezones use world-clock. Input: lat/lng or geohash. Returns geohash or coords. 100% client-side, files never leave browser.
Reverse text by characters (grapheme-safe for emoji), words, or lines.
Decode Base64 to UTF-8 text with URL-safe support and error location. Use when decoding only; for full encode+decode workflow use base64. Input: Base64 string ≤10MB. Returns decoded text or INVALID_BASE64 with position. 100% client-side.
Encode UTF-8 text to Base64 with URL-safe mode. Use when encoding only; for full encode+decode workflow use base64. Input: text ≤10MB. Returns Base64 string. 100% client-side.
Minify CSS for production by stripping whitespace. Alias view of css-formatter in minify mode; prefer css-formatter for full workflow. Input: CSS ≤10MB. Returns minified CSS. 100% client-side.
Build cron schedules with plain-English preview. Use for automation timing. Input: fields or presets. Returns expression + next runs. 100% client-side.
Converts between Arabic numbers and Roman numerals with validation. Use for chapters, clocks or outlines; differs from base-converter by Roman symbols vs positional bases. Returns numeral or number. 100% client-side.
Look up MAC vendor from OUI prefix. Use for device ID; for new MACs use mac-address-generator. Input: MAC address. Returns vendor. 100% client-side.
Pick colors from uploaded images. Use when sampling images; for conversion use color-converter, for palette use color-picker. Input: image ≤10MB. Returns HEX/RGB. 100% client-side, files never leave browser.
Generate URL slugs from titles with lowercase rules. Use as default slug tool; slugify-string is a noindex alias. Input: text ≤10MB. Returns slug string. 100% client-side.
Look up MIME types by extension and vice versa. Use when configuring uploads; for file checksums use file-checksum. Input: extension or MIME. Returns MIME mapping. 100% client-side.
Obfuscate strings with masking and reversible transforms. Use when hiding PII in demos; for hashing use hash-generator. Input: text ≤10MB. Returns obfuscated text. 100% client-side.
Calculate chmod permissions from checkboxes or octal. Use when setting file modes; for git perms use git-cheatsheet. Input: mode or ticks. Returns octal and symbolic. 100% client-side.
Analyze cyclomatic complexity and code metrics. Use when reviewing quality; for formatting use js-minifier. Input: code ≤10MB. Returns complexity scores. 100% client-side.
Plans house down payment from target price, percent, timeline and savings rate. Use when saving for a first home; differs from savings-goal-calculator by closing costs vs generic goal. Returns monthly savings needed and milestones. 100% client-side.
Computes flat interest from principal, rate and time without compounding. Use for short-term loans or quick estimates; differs from compound-interest-calculator by linear growth vs compounding. Returns interest, total payable and split. 100% client-side.
Adjusts money for inflation from amount, rate and years. Use when valuing future costs; differs from compound-interest-calculator by purchasing power vs investment growth. Returns future cost, real value today and yearly table. 100% client-side.
Show current time across timezones. Use when scheduling; for timestamps use timestamp-converter. Input: timezone selection. Returns local times. 100% client-side, files never leave browser.
Build JS benchmarks comparing snippets. Use when comparing speed; for regex testing use regex-tester. Input: JS snippets. Returns ops/sec table. 100% client-side, files never leave browser.
Create structured AI prompts from a goal. Use for starter prompts. Input: topic text ≤10MB. Returns prompt template. 100% client-side.
Pick random free ports for dev servers. Use for local testing. Input: count/range options. Returns port numbers. 100% client-side.
Convert between TOML, JSON, and YAML in any direction. Use for multi-format configs; for single-pair JSON-YAML use json-to-yaml. Input: TOML/JSON/YAML ≤10MB. Returns converted text or parse error. 100% client-side.
Shows Unicode code points, names and UTF-8 bytes for any text. Use when debugging encoding issues; differs from nato-alphabet by code points vs phonetic words. Returns per-character table with escapes. 100% client-side.
Validate IBANs with checksum + country check. Use for bank transfers. Input: IBAN text. Returns valid/invalid + details. 100% client-side.
Count characters, words, lines, and bytes. Use for quick length checks; for full stats use word-counter. Input: text ≤10MB. Returns counts. 100% client-side.
Show browser, OS, screen, and network details. Use for live device data; for parsing UA strings use user-agent-parser. Input: none, auto-detected. Returns device table. 100% client-side.
Stopwatch and timer with laps in browser. Use when timing tasks; for date spans use date-calculator. Input: button controls. Returns elapsed time. 100% client-side.
Expand CIDR or dash ranges into IP lists. Use when enumerating hosts; for subnet calc use ipv4-subnet-calculator. Input: range text. Returns IP list. 100% client-side.
Compute similarity % and Levenshtein distance between strings. Use for fuzzy match scoring; for visual diff use text-diff-visual. Input: two strings ≤10MB. Returns similarity + distance. 100% client-side.
Totals net worth from listed assets and liabilities. Use for periodic wealth checkups; differs from emergency-fund by full balance sheet vs months of expenses. Returns net worth, asset/liability split and ratio. 100% client-side.
Annualized return for irregularly dated cash flows, Excel-style. Result stays in your browser
Rewrite rough prompts for clarity and context. Use for better AI output. Input: draft prompt ≤10MB. Returns improved prompt. 100% client-side.
Spells numbers as English words with currency and ordinal options. Use for cheques, invoices or legal text; differs from text-to-unicode by words vs code points. Returns word form and copy-ready text. 100% client-side.
Generate random MAC addresses. Use for testing; for vendor lookup use mac-address-lookup. Input: count/format options. Returns MACs. 100% client-side.
Unwrap safelink and redirect URLs to real destination. Use when verifying links; for URL parts use url-parser. Input: wrapped URL. Returns final URL. 100% client-side.
Estimate arrival time and duration from speed and distance. Use when planning transfers; for date math use date-calculator. Input: numbers. Returns ETA and duration. 100% client-side.
Sizes an emergency buffer from monthly expenses and months of cover. Use when building a safety net; differs from savings-goal-calculator by expense coverage vs dated target. Returns target fund, monthly plan and progress. 100% client-side.
Translate text to Morse code and back. Use for learning or signaling. Input: text ≤10MB. Returns dots/dashes or decoded text. 100% client-side.
Spells text as NATO phonetic words (Alpha, Bravo, Charlie). Use when dictating over calls; differs from text-to-unicode by spoken words vs code points. Returns phonetic transcription. 100% client-side.
Show key code and key name for any pressed key. Use when debugging shortcuts; for regex keys use regex-tester. Input: key press. Returns code details. 100% client-side.
Normalize email addresses for dedup and login matching. Use when cleaning lists; for validation use regex-tester. Input: emails ≤10MB. Returns normalized list. 100% client-side.
Generate private IPv6 ULA prefixes per RFC 4193. Use for lab networks; for subnet math use ipv6-calculator. Input: optional seed. Returns ULA prefix. 100% client-side.
Shorten long words to numeronyms (i18n, a11y). Use for abbreviations. Input: word ≤10MB. Returns numeronym. 100% client-side.
Copy EXIF metadata between images. Use when preserving metadata; for viewing use exif-reader. Input: 2 images ≤10MB. Returns image with EXIF. 100% client-side, files never leave browser.