Ratio Calculator

Ratio

Simplify A:B ratios, split totals by a ratio, solve A:B=C:D, and calculate additions needed to reach a target ratio.

Simplify A:B ratio

Show the simplest ratio and each side's share of the total.

A value B value

Enter values to calculate. Simplifies A:B to the smallest integer ratio.

Split by ratio

Split a total amount or quantity by an A:B ratio.

Total value A ratio B ratio

Enter values to calculate. Total value × each ratio ÷ ratio sum

Find fourth proportional value

Enter A, B, and C to find D in A:B = C:D.

A value B value C value

Enter values to calculate. D = B × C ÷ A

Match a target ratio

Calculate which side to add so current A and B match a target ratio.

Current A value Current B value Target A ratio Target B ratio

Enter values to calculate. Add the missing side so current A:B matches the target A:B

When to use this calculator

Simplify A:B ratios, split totals by a ratio, solve A:B=C:D, and calculate additions needed to reach a target ratio.

Dividing a budget, recipe, or workload fairly
Scaling measurements while preserving proportions
Finding a missing fourth value in a proportion

Worked examples

Simplifying a ratio

24:36 reduces to 2:3 after dividing both sides by 12.

Ratio split

100,000 split at 2:3 becomes 40,000 and 60,000.

Proportion

For 2:3 = 10:D, D is 15.

Frequently asked questions

Can decimal ratios be simplified?

Yes. The calculator scales decimals to integers before reducing them.

Can both sides be zero?

No. A 0:0 ratio has no meaningful proportion.

Does rounding affect a split?

Displayed values may be rounded, so the visible parts can differ slightly from the total for repeating decimals.

How to interpret the result

Use values measured in the same unit before comparing them.

For legal or financial allocations, apply the required remainder and rounding policy separately.