A Ratio Calculator

A ratio is a division you have decided to keep as a pair, and the two things you do with it are comparing sizes and splitting a whole.

First partThe first term of the ratio, for example 3 in 3 to 2.Second partThe second term of the ratio, for example 2 in 3 to 2.Total to splitSet to 0 if you only want the ratio value and the percentage.

Ratio value

1.5

Ratio as a percentage: 150.00%
First share: $600.00
Second share: $400.00

Values update as you type. This calculator covers the single scenario its formula assumes — see Common Mistakes for what it leaves out.

The formula this calculator uses

ratio value = first quantity / second quantity; share = total x quantity / (sum of all quantities)

a: First quantity
b: Second quantity
T: Total to split

How to check the result by hand

1
Put both quantities in the same unit
Convert so that both sides use the same unit before you divide. A comparison of 2 hours to 45 minutes becomes 120 minutes to 45 minutes, not 2 to 45.
2
Divide to get the value
Divide the first quantity by the second. Three divided by two is 1.5, which is the ratio value and also 150 percent.
3
Add the parts
To split a total, add the ratio terms first. Three plus two is five, and five is the number of shares the total is divided into.
4
Allocate and check
Divide the total by the sum, multiply by each part, then add the shares back up to confirm they equal the original total.

For worked examples, common mistakes and the limits of this formula, read the full How To Calculate A Ratio page.