Proportion Calculator

โšก Solve proportions, scale recipes, calculate map distances & more! Instant step-by-step solutions for homework and real life.

The Ultimate Proportion Calculator

Master proportions with our free calculator! Solve basic proportions, scale recipes for any number of servings, calculate real distances from maps, or work with direct and inverse proportions. Every calculation includes step-by-step solutions to help you understand the math. Used by millions of students and home cooks worldwide.

Cross Multiplication

a/b = c/d โ†’ a ร— d = b ร— c

Solve any proportion by cross multiplying

Recipe Scaling

New Amount = Original ร— (New Servings / Original Servings)

Scale any ingredient proportionally

Map Scale

Real Distance = Map Distance ร— Scale Factor

Convert map measurements to real distances

Direct Proportion

y = kx, where k = y/x

y increases as x increases

Inverse Proportion

xy = k

y decreases as x increases

Examples

Solve: 3/4 = x/20

1Cross multiply: 3 ร— 20 = 4 ร— x
260 = 4x
3x = 15

Scale recipe from 4 to 6 servings

1Scale factor = 6/4 = 1.5
2Multiply each ingredient by 1.5
32 cups flour โ†’ 3 cups

Map scale 1:50000, 3cm = ?

1Real = 3 ร— 50000 = 150000 cm
2= 1500 m = 1.5 km

Frequently Asked Questions

How do I scale a recipe?

Divide your desired servings by the original servings to get the scale factor. Multiply every ingredient by this factor. For example, scaling from 4 to 6 servings: 6รท4 = 1.5, so multiply all ingredients by 1.5.

How do I calculate real distance from a map?

Multiply the map measurement by the scale factor. For a 1:50000 map, 1cm on the map = 50000cm (500m) in real life. So 3cm on the map = 1.5km real distance.

What is the difference between direct and inverse proportion?

In direct proportion (y = kx), when x increases, y also increases. In inverse proportion (xy = k), when x increases, y decreases. Example: More workers = less days to finish (inverse).

Is this calculator free?

Yes! 100% free with no signup. Get instant step-by-step solutions for all your proportion problems.