Ratio Calculator

Simplify a ratio to lowest terms or solve for the missing value in a proportion.

What does this Ratio Calculator do?

This Calculator simplifies a two-part ratio to lowest terms or solves a proportion when one side of the ratio is known. It supports decimal ratio parts and positive known values.

Formula

Simplify A:B by dividing both parts by their greatest common factor after scaling decimals to integers. Find B when A is known: B = Known A × Ratio B ÷ Ratio A. Find A when B is known: A = Known B × Ratio A ÷ Ratio B.

Worked example

The ratio 10:15 simplifies to 2:3. In a 2:3 proportion, if A is 10 then B is 10 × 3 ÷ 2 = 15.

Assumptions and limitations

All ratio parts and known values must be greater than zero. The Calculator does not reduce ratios that include negative values or interpret units beyond the entered numbers.

Common questions

Can I simplify decimal ratios?

Yes. The Calculator scales decimal parts to integers before dividing by their greatest common factor. How is this different from percentage tasks? Percentages express part-whole relationships as percents. Ratios compare two quantities directly. Can I solve either side? Yes. Choose whether A or B is the known value.

Methodology

The Calculator scales ratio parts to integers, applies greatest-common-factor reduction, and uses exact decimal arithmetic for proportion solving. Display values are rounded only for presentation.