Free Ratio Calculator — Simplify & Scale Ratios Online
Simplify ratios, scale proportions, and solve for missing values — instantly in your browser with no signup needed.
Simplified
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How it works
Choose a mode
Select Simplify (reduce A:B) or Scale (find missing value in A:B = C:?).
Enter your values
Type the numbers into the input fields.
Get your result
The simplified ratio or missing value appears instantly.
Use the decimal form
The decimal equivalent and percentage split are shown for easy reference.
Common use cases
Recipe scaling
Scale recipe ingredient ratios up or down while keeping proportions accurate.
Map & scale drawings
Solve scale problems like "if 1cm = 5km, how far is 7cm?"
Mixing & dilution
Calculate correct mixing ratios for paints, chemicals, or solutions.
Financial ratios
Simplify financial ratios like debt-to-equity for quick comparison.
Frequently asked questions
How does ratio simplification work?
Both values are divided by their Greatest Common Divisor (GCD), reducing the ratio to its lowest terms.
What is cross-multiplication?
In the proportion A:B = C:D, if D is unknown: D = (B × C) / A. This finds the missing fourth value.
Can I use decimals in ratios?
Yes — decimal inputs are supported. The tool converts them to the simplified form.
What does a ratio of 1:1 mean?
Equal parts. A 1:1 ratio means both quantities are the same.
Is this calculator free?
Yes, completely free with no account needed.
Is my data private?
Yes — all calculations run in your browser. Nothing is sent to a server.