Free Ratio Calculator
Simplify a ratio or solve a proportion — no signup, nothing sent to a server.
Simplified:
How to use the ratio calculator
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1
Pick a calculation type
Choose "Simplify a ratio" or "Solve A:B = C:?" from the tabs above.
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2
Enter your numbers
Type the values into the fields — the result updates instantly as you type.
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3
Read the result
The simplified ratio or missing value appears below the inputs.
Example use cases
Recipe scaling
Keep ingredient ratios consistent when scaling a recipe up or down.
Mixing solutions
Work out mixing ratios for paint, concrete, or cleaning solutions.
Maps & scale models
Solve proportions for scale drawings, maps, and models.
Finance & aspect ratios
Simplify ratios for financial statements or screen/image dimensions.
Frequently asked questions
How do I simplify a ratio?
Divide both numbers by their greatest common divisor (GCD). For example, 8:12 has a GCD of 4, so it simplifies to 2:3.
How do I solve a proportion like A:B = C:?
Cross-multiply and divide: the missing value equals (B × C) ÷ A. For example, 2:5 = 8:? gives (5 × 8) ÷ 2 = 20.
Can I use decimals?
Yes, both tabs accept decimal values, though the "Simplify" tab works best with whole numbers since it uses the greatest common divisor.
Is anything I type sent to a server?
No. Every calculation runs entirely in your browser — nothing is transmitted or logged.