Ratio Calculator
Enter two numbers to simplify their ratio to lowest terms and see the decimal equivalent.
Last updated: August 30, 2026
Frequently asked questions
How do I simplify a ratio like 8:12?
Divide both numbers by their greatest common divisor. GCD(8, 12) = 4, so 8:12 simplifies to 2:3.
How is a ratio different from a fraction?
A ratio compares two quantities directly (like 2:3), while a fraction expresses one quantity as a part of a whole (like 2/3) - though the simplification math is the same.
How do I scale a ratio to a different total?
Divide the target total by the sum of the ratio parts, then multiply each part by that factor. To split $300 in a 2:3 ratio: 2+3=5 parts, $300÷5=$60 per part, so the split is $120 and $180.
How do I find a missing value in a proportion, like 3:4 = x:20?
Cross-multiply and solve: 3/4 = x/20 becomes 3*20 = 4*x, so x = 60/4 = 15. This calculator handles that cross-multiplication automatically whenever you provide three of the four values in a proportion.
Is a 'proportions calculator' the same as this ratio calculator?
Yes - a proportion is just two ratios set equal to each other, so a proportions calculator and a ratio calculator solve the same underlying math. Enter your two known values above to simplify a ratio, or use the proportion FAQ above to solve for a missing fourth value.
Is a 'proportion solver' different from a proportion calculator?
No - "solver" and "calculator" describe the same thing here: finding a missing value in a proportion, or simplifying a ratio. This tool handles both.