Math calculator

Ratio Calculator

Simplify a ratio to lowest whole-number terms or solve one missing value in an equivalent ratio.

Enter at least two positive whole numbers, separated by colons, commas, or spaces.

Simplified ratio

How it works

Simplification divides every positive whole-number term by their greatest common factor. Equivalent-ratio mode instead solves a proportion with one unknown using cross multiplication.

Simplified terms = each term ÷ GCF

Worked example

For 8:12, the greatest common factor is 4, so 8 ÷ 4 : 12 ÷ 4 = 2:3.

How to use this tool

  • Enter the known values and choose units where available.
  • Check the primary result and supporting details.
  • Clear or replace an input to calculate another case.

Frequently asked questions

What happens with invalid or incomplete inputs?

The result remains blank until the required inputs form a finite, meaningful calculation. Zero denominators and physically impossible negative quantities are not calculated.

Can I use decimal values?

Yes. The tool accepts decimals and keeps full precision for the calculation while rounding the displayed result for readability.