Simplify a ratio to lowest terms, see it as a decimal, and scale it to an equivalent ratio.
How this calculator arrives at its answer
Enter two numbers and this ratio calculator reduces them to lowest terms and shows the decimal value. Add a third number to solve an equivalent ratio (A : B = C : ?).
It’s handy for recipes, scale models, mixing and aspect ratios.
Try it with these numbers
On the values this calculator opens with, the simplified ratio is 16 : 9. Alongside it, Decimal comes out at 1.7778. Change any field and every figure updates as you type.
Getting your answer
- Enter the two parts of the ratio.
- Read the simplified ratio and decimal.
- Enter a scale value to find the equivalent ratio.
How the number is calculated
simplify: divide both by their greatest common divisor
scale: A : B = C : (B × C ÷ A)
Common questions
How do I simplify a ratio?
Divide both numbers by their greatest common divisor. 16:9 is already lowest terms; 20:30 simplifies to 2:3.
How do I scale a ratio?
Keep the proportion the same. For 16:9 scaled to width 32, the height is 9 × 32 ÷ 16 = 18, so 32:18.
Can ratios have decimals?
Yes — the tool shows the decimal value (A ÷ B) alongside the simplified whole-number ratio.