How to use Ratio Calculator
A ratio compares the size of two quantities. Simplifying divides both parts by their greatest common divisor while preserving the comparison. For example, 60:90 simplifies to 2:3.
The percentage shares describe the two parts within their combined total. This tool accepts positive whole numbers; scale decimal quantities to whole numbers before simplifying, while keeping both parts on the same scale.
The formula
Simplified ratio = (A / gcd(A, B)) : (B / gcd(A, B))
First share = A / (A + B) × 100
A worked example
First part: 60 · Second part: 90
Simplified ratio: 2 : 3
Questions about this calculation
How do I simplify 1.5:2.5?
Multiply both parts by 10 and enter 15 and 25.
Does 2:3 mean 2 is 66.7% of the total?
No. The first share is 2 divided by 5, or 40%. It is 66.7% of the second part.
Formula checks: 2026-10-08. Assumptions & corrections.