How to use this calculator
- Choose the type of calculation from the list.
- Enter the two values. The labels change to match the question.
- The answer updates instantly, with the equation used shown below the result.
Formula
A percentage is a fraction of 100. Every percentage problem is a rearrangement of part = percent × whole / 100.
X% of Y = X / 100 × Y
X is what % of Y = X / Y × 100
% change from A to B = (B − A) / |A| × 100
% difference = |A − B| / ((A + B) / 2) × 100
Examples
- 15% of 200 = 0.15 × 200 = 30.
- 30 is what % of 120? 30 / 120 × 100 = 25%.
- From 80 to 100: (100 − 80) / 80 × 100 = 25% increase.
- 200 increased by 15% = 200 × 1.15 = 230.
Frequently asked questions
Is percentage change the same as percentage difference?
No. Percentage change has a direction (from an old value to a new one). Percentage difference compares two values symmetrically, using their average as the base.
Why isn't a 50% increase followed by a 50% decrease back to the start?
Because the decrease applies to the larger number. 100 + 50% = 150, and 150 − 50% = 75.
What is a percentage point?
It's the simple difference between two percentages. Going from 4% to 5% is an increase of 1 percentage point, but a 25% relative increase.