math calculator

Ratio Calculator

Simplify any ratio to its lowest terms and see the exact proportion between two values. for scaling recipes, mixing paints, designing layouts or understanding gear ratios.

Important Use Notice

Informational calculator only. Verify important outputs independently before legal, tax, medical, engineering, safety-critical, contractual, employment, or compliance use.

Estimate

Enter job values, review the estimate, then use the decision hints before ordering or quoting.

First value

Second value

Estimate Results

Enter values to see the result.

Example

12:18 → divide by 6 → 2:3

Formula

Simplified a:b = (a ÷ GCD(a,b)) : (b ÷ GCD(a,b))

GCD is the greatest common divisor. Divide both numbers by GCD to get lowest terms.

Decimal ratio = a / b

Check

Forgetting to reduce to lowest terms
Confirm that all inputs use the same unit system expected by the formula.

Next Step

Next Calc

Proportion Calculator

This proportion calculator helps when a, b, c are already known and you want the x quickly.

Next Calc

Ratio to Percent Calculator

Next: ratio to percent.

Next Calc

Direct Proportion Calculator

Next: direct proportion.

FAQ

What if numbers are decimals?

Multiply both by the same power of 10 to make integers, simplify, then divide back if needed.

How is ratio different from fraction?

Ratio compares two things (a to b), fraction is part of a whole (a/b).