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Ratio Calculator

Simplify ratios, find missing values, check if ratios are proportional, and scale recipes, maps, and measurements.

Simplify Ratio
Ratio
:
Proportion — Find Missing Value

a : b = c : d — leave one blank

a
b
c
d (solve for)
Ratio to Fraction / Decimal / Percentage
Simplified Ratio
3 : 2
GCF = 4
FormValue
Scale / Multiply Ratio
Original ratio
:
Scale factor

Ratios Explained

A ratio compares two or more quantities. The ratio 3:2 means "for every 3 of one thing there are 2 of another." Ratios can be simplified by dividing both parts by their GCF.

Proportions

A proportion states that two ratios are equal: a/b = c/d. Cross-multiplication: a×d = b×c. Used extensively in cooking, maps, scale models, and engineering.