Ratio Calculator

Solve ratios and scale them instantly! Enter values for A:B = C:D, or enlarge/shrink any ratio by a scale factor.

Perfect for adjusting recipes, scaling drawings, or solving math problems. Fast, accurate, and easy-to-use — no formulas needed!

Ratio Calculator – How It Works

The Ratio Calculator is a versatile tool designed to help you solve problems involving proportional relationships quickly and accurately. It supports three main modes:


Ratios are everywhere — from cooking and baking to scaling models, drawings, or financial comparisons. With this tool, you can:


The calculator ensures accurate results and provides clear feedback if inputs are incomplete or invalid. It's perfect for students, professionals, and anyone working with ratios in daily life.


How to use:


Frequently Asked Questions

A ratio compares two quantities to show how large one is compared to the other. For example, a ratio of 2:5 means that for every 2 parts of one quantity, there are 5 parts of another.
If you know three of the four values, the missing one can be found using proportion rules. This calculator does the math instantly, so you only need to enter the known values.
Enlarging a ratio multiplies both parts by the same scale factor. For example, enlarging 3:4 by 2 creates 6:8.
Shrinking divides both parts of the ratio by the same factor. For example, shrinking 10:20 by 2 gives 5:10.
Ratios are used in cooking, map scaling, construction, modeling, finance, statistics, and many school math problems.