Tiny Toolkit

Ratio Calculator — Simplify Ratios & Solve Proportions

Reduce any ratio to its simplest form using the GCD algorithm, or solve a proportion to find a missing value in A:B = C:X. Both modes update in real time. Useful for scaling recipes, reading map scales, comparing rates, and any situation where you need to reason about relative quantities.

All processing happens in your browser. No data is sent to any server.

Frequently Asked Questions

How do you simplify a ratio?
Divide both values by their Greatest Common Divisor (GCD). For example, 12:8 → GCD is 4 → simplified to 3:2.
What is a proportion?
A proportion states that two ratios are equal: A:B = C:X. If you know three of the four values, you can solve for the missing one using cross-multiplication: X = (B × C) / A.
What is a ratio used for?
Ratios are used in cooking (recipe scaling), maps (scale ratios), finance (P/E ratios), photography (aspect ratios), and many other real-world contexts.

Related Tools

Percentage Calculator — 3 Ways to Calculate Percentages

Calculate what percent of a number is, find a percentage change between two values, or determine what percent one number is of another. Three calculators in one. Free.

Age Calculator — Exact Age in Years, Months & Days

Calculate your exact age in years, months, and days from any date of birth. Also shows your next birthday and how many days until it. Free, instant results.

Days Until Date Calculator — Countdown to Any Date

Count the exact number of days, weeks, and months until any future date. Great for countdowns, deadlines, and event planning. Updates in real time. Free.