Loading…
Simplify ratios, split a total in a given ratio, and solve proportions a:b = c:x.
Ratio Calculator is loading — interactive editor will appear here. Use examples below to try instantly once loaded.
Press ? for keyboard shortcuts
Works with ratios in three ways: simplifies a:b to its lowest whole-number terms, splits a total into two parts in a given ratio, and solves a proportion a:b = c:x for the unknown x.
Ratios show up everywhere — recipes, maps, screen aspect ratios, paint mixing, financial analysis. Doing them by hand involves finding the greatest common divisor or cross-multiplying, which is error-prone; this calculator shows both the result and the reasoning.
This tool is part of the DevStackIO platform — a collection of free online developer tools from DevStackIO. Browse more free developer resources on DevStackIO.
Students learning proportions, cooks scaling recipes, designers computing aspect ratios, mixologists and formulators blending to a ratio, and analysts splitting costs or budgets.
Pick a mode: Simplify a:b, Split total by ratio, or Solve a:b = c:x
Enter the terms (a and b; plus a total or c as needed)
Read the result headline and the step explanation below it
Decimals are scaled to whole numbers automatically in simplify mode
Simplify 12:18 → 2:3Simplify 0.5:0.25 → 2:1Split 100 in the ratio 1:3 → 25 and 75Solve 2:3 = 10:x → x = 15Simplify 1280:720 → 16:9Q: Can I simplify ratios with decimals? A: Yes
decimals are scaled to whole numbers first, so 0.5:0.25 becomes 2:1.
Q: How does proportion solving work?
A: Cross-multiplication: a:b = c:x means x = c × b ÷ a.
Q: What about ratios with three or more terms? A: This tool handles two-term ratios; for three terms, simplify each pair with the GCD of all terms
see the GCD & LCM Calculator.
Q: Is the simplified form unique? A: Yes
dividing both terms by their GCD gives a unique lowest-terms integer ratio.
Authoritative specifications, standards, and in-depth reading for Ratio Calculator.
2 : 3
12:18 reduces by their greatest common divisor. As a fraction: 0.666667.
Simplification uses the greatest common divisor; decimals are scaled to whole numbers (0.5:0.25 → 2:1). Runs locally.
Add, subtract, multiply, and divide fractions with exact rational arithmetic — no floating-point drift. Simplifies automatically.
Greatest common divisor and least common multiple of two or more numbers via Euclid's algorithm.
Descriptive statistics for a list of numbers: mean, median, mode, range, variance, standard deviation.
Compute nCr (combinations) and nPr (permutations) with exact integer arithmetic. Supports large n via logarithms.
Solve ax² + bx + c = 0, including complex conjugate roots.
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.
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.
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.