Loading…
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.
Base64 Decoder is loading — interactive editor will appear here. Use examples below to try instantly once loaded.
Press ? for keyboard shortcuts
A dedicated standalone Base64 decoder that automatically detects whether input contains valid Base64 content and determines the original encoding type. Features include automatic encoding detection (UTF-8, ASCII, UTF-16LE, UTF-16BE), downloadable decoded output as a binary file, real-time validation with error highlighting, and a clean single-purpose interface focused exclusively on decoding.
Users often need a focused tool that handles Base64 decoding without the clutter of an encoder. A standalone decoder reduces cognitive load by presenting exactly the controls needed, with automatic detection that eliminates guesswork about input format and source encoding.
This tool is part of the DevStackIO platform — a collection of free online developer tools from DevStackIO. Browse more free developer resources on DevStackIO.
Security researchers analyzing encoded payloads, developers debugging Base64 data from APIs, QA engineers verifying encoded assets, and anyone who primarily decodes rather than encodes.
Paste the Base64 string into the input area or drag-and-drop a text file containing the Base64 data
The tool automatically detects if the input is valid Base64 — invalid characters are highlighted in red
Review the detected source encoding (UTF-8, ASCII, UTF-16LE, UTF-16BE) shown in the status bar
Click 'Decode' — decoded output appears in the result panel with byte-by-byte breakdown if binary
If the decoded output is binary, use 'Download' to save it as a file with the correct extension
Copy decoded text to clipboard directly, or use 'Download as Text' for non-binary output
Input: 'SGVsbG8gV29ybGQh' | Auto-detect => Output: 'Hello World!' (decoded to UTF-8 text)Input: 'iVBORw0KGgo...' (PNG) | Auto-detect => Output: [binary PNG] | Download as 'decoded.png'Can this tool decode base64url?
Yes, base64url is automatically detected and decoded.
How does encoding detection work?
It examines byte patterns and BOM markers for UTF-16 vs UTF-8 vs ASCII.
What if my decoded output is garbled?
Try switching source encoding manually. Auto-detection may be wrong for short strings.
Can I decode large strings?
Yes, but multi-megabyte strings may take a few seconds.
Authoritative specifications, standards, and in-depth reading for Base64 Decoder.
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.
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.
Free online URL encoder and decoder for query strings and components. Private client-side conversion.
Encode/decode HTML entities (& < >). Use for HTML text; for URLs use url-encoder. Input: text ≤10MB. Returns encoded/decoded text. 100% client-side.
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 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.
Escape/unescape JS strings. Use for code literals; for JSON strings use json-escaper. Input: text ≤10MB. Returns escaped text. 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.