Ratio Calculator
Simplify a ratio, share a total in that ratio, or fill in a missing term in a proportion.
About this calculator
A ratio compares two quantities. This calculator reduces a ratio to lowest terms, splits a total into parts that keep a given ratio, and solves for a missing term in a proportion.
How to calculate
Pick a mode. Simplify uses two numbers and their greatest common divisor. Split divides a total into parts. Missing term solves a:b = c:x.
a:b simplified = (a ÷ gcd) : (b ÷ gcd)
Part A = Total × a / (a + b)
x = b × c / a
When to use it
- Splitting a cost 2:1
- Scaling a mix from 3:5 to a larger batch
Examples
Simplify 12:18
The greatest common divisor of 12 and 18 is 6, so 12:18 simplifies to 2:3.
Split 100 in 2:3
The parts are 40 and 60, because 2/5 of 100 is 40 and 3/5 of 100 is 60.
Simplified ratios
| Ratio | Simplified |
|---|---|
| 8:12 | 2:3 |
| 15:25 | 3:5 |
| 100:40 | 5:2 |
FAQ
Can ratios include decimals?
Yes. The calculator accepts decimals. Simplifying still uses a greatest common divisor after scaling to integers when possible.
What if one side of the ratio is zero?
A ratio with a zero term cannot be simplified in a useful way, and a proportion cannot be solved if the known corresponding term is zero.