Simplify a:b
Divide a and b by their greatest common divisor.
Ratio Calculator
Simplify a:b ratios and solve a:b = c:x proportions.
Simplify a:b
Solve a:b = c:x
A ratio compares the relative size of two values
Ratios show up in screen sizes, recipes, map scales, unit prices, and many everyday comparisons. This calculator reduces a:b to its simplest whole-number form and solves the missing x in a proportion written as a:b = c:x.
Formulas
Proportion
If a:b = c:x, then x = (b × c) ÷ a
Examples
1920:1080 → 16:9, 2:3 = 10:x → x = 15
How to use
- For ratio simplification, enter the a and b values.
- For proportion solving, enter a, b, and c; x appears instantly.
- When values have units, convert them to the same unit before calculating.
Frequently asked questions
Why does 1920:1080 become 16:9?
The greatest common divisor of 1920 and 1080 is 120. Dividing both by 120 gives 16 and 9.
Can I enter decimal ratios?
You can enter numeric values, but simplification uses rounded whole numbers. For precise decimal ratios, scale the units first so the inputs become integers.
What if a is 0 in a:b = c:x?
The formula divides by a, so x is not defined when a is 0.
This tool is for general arithmetic. For official figures such as taxes or finance, confirm with the relevant authority.