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Ratio Calculator
Simplify a ratio to its lowest terms, or solve A : B = C : X for the missing value. Decimals are fine.
Simplify a ratio
Solve A : B = C : X
The method
simplify: divide A and B by gcd(A, B) solve: A : B = C : X -> X = B x C / A
Worked examples
| Question | Answer |
|---|---|
| Simplify 6 : 4 | 3 : 2 |
| Simplify 1.5 : 2 | 3 : 4 |
| 2 : 3 = 10 : X | X = 15 |
| 16 : 9 = 1920 : X | X = 1080 |
Scaling a recipe is the same sum: if 2 cups of rice make 3 servings, 10 cups make 15. To express a part as a share of the whole, use the percentage calculator.
Frequently asked questions
How do I simplify a ratio?
Divide both numbers by their greatest common divisor. For 6:4 the divisor is 2, so the ratio simplifies to 3:2.
How do I simplify a ratio with decimals?
Multiply both numbers by the same power of 10 to make them whole, then simplify. 1.5:2 becomes 15:20, which simplifies to 3:4.
How do I find the missing number in a ratio?
Use cross-multiplication. For A:B = C:X, X = B x C / A. If 2:3 = 10:X, then X = 3 x 10 / 2 = 15.
How do I scale a ratio for a screen or image?
For a 16:9 screen that is 1920 wide, the height is 9 x 1920 / 16 = 1080.
Is a ratio the same as a fraction?
They are related but not identical. The ratio 3:2 compares two parts to each other. As fractions of the whole, the parts are 3/5 and 2/5.