Ratio Calculator

How to use

1. 1Pick a mode at the top: Simplify a ratio, Solve a proportion, Scale to a total, or Equivalent ratios.
2. 2In Simplify, type two or more positive numbers (use Add part for three-part ratios) and read the reduced ratio, fraction, decimal, percent, and share-of-total chart.
3. 3In Solve, fill three of the four A:B = C:D boxes and leave the unknown blank. The tool solves it with cross multiplication and shows the step-by-step work.
4. 4In Scale, enter a ratio plus a total. The total is divided across the parts according to their share, with optional labels for each row.
5. 5In Equivalent, enter two numbers and choose how many rows. The tool lists ratios that all equal your starting value, starting from the reduced form.

About this tool

Ratio Calculator is a four-mode toolkit for everyday ratio questions. Simplify mode takes a ratio of two or more positive numbers (24:36, 1920:1080, 2:4:6, or even decimals like 3.5:7) and reduces it to lowest terms using the greatest common divisor, then prints the simplified ratio, the equivalent fraction, the decimal form (A divided by B), the inverse decimal, the percent that one part represents of the other, and a share-of-total bar for each part so a three-part ratio like 3:2:1 reveals itself as 50% / 33.3% / 16.7%. Solve mode handles the classic proportion a:b = c:d: fill three of the four boxes, leave one blank, and the tool solves for the unknown using cross multiplication (A times D equals B times C) and prints the step-by-step substitution so a student can copy the work onto a homework sheet. Scale mode distributes a total across the parts of a ratio: it accepts colons, slashes, dashes, commas, or spaces as separators between parts, and turns 600 split 3:2:1 into 300 / 200 / 100, 50,000 split 70:30 into 35,000 / 15,000, or 60 kg of concrete mix split 1:2:3 into the correct cement, sand, and gravel weights, with optional labels for each row. Equivalent ratios mode starts from the reduced form of a:b and lists 1x, 2x, 3x, and so on up to 50 multipliers in a copyable table, which is exactly what teachers and students use when filling out a ratio table or when picking a whole-number pair that matches a target dimension. Useful for math homework on proportions and equivalent ratios, recipe scaling when you need to grow or shrink ingredient amounts, splitting a check or a partnership profit by agreed shares, mixing concrete, fuel, paint, or chemical solutions to a target weight or volume, simplifying odds and probabilities, sanity-checking aspect ratios when the dedicated aspect-ratio tool is not the right shape of question, and converting between ratio, fraction, decimal, and percent in one place. Every calculation runs in your browser using deterministic IEEE 754 arithmetic; the numbers you type never leave your device.

Free to use. Works in your browser. No signup, no login.