Lab · Calculators

Proportion calculator

Select direct or inverse proportion, enter three values, and calculate the fourth.

Three known values

Select the relationship and the value to calculate, then enter the other three.

Value kind

Quantities A and B can have arbitrary labels; their values are not converted between units.

Proportion type

When A changes by a factor, B changes in the same direction by that factor.

?
?
?
?
Labels and units

Units apply to both situations, are displayed only, and are not converted.

Enter the three known values.

Incomplete

Value relationship

Similar rectangles show both quantities growing or shrinking by the same factor.

Entered Calculated
Value relationship Technical diagram of two situations with four dimensions, a change factor, and a direct or inverse proportion equation. Situation 1 Situation 2 ? ? ? ? A, B × k A₁ / B₁ = A₂ / B₂

All values

A₁ · Situation 1
—
B₁ · Situation 1
—
A₂ · Situation 2
—
B₂ · Situation 2
—
Change factor for A
—

Relationship used

—

—

Calculations use full precision; only the output is rounded. Units are labels only and are not converted.