How to use
- Pick the calculator you need.
- Enter the two known values.
- The result appears instantly – including the formula.
Percentages explained
A percentage calculation involves three values: the base (the whole), the rate (the share in %) and the part (the share as a number). The basic formula is: part = base × rate ÷ 100.
Percentage change shows by how many percent a value has gone up or down – for prices, salaries or stock prices, for example.
Frequently asked questions
How do I calculate 20% of 150?
150 × 20 ÷ 100 = 30. Just enter 20 and 150 in the first calculator.
How do I calculate a percentage increase?
(New value − old value) ÷ old value × 100. Going from 80 to 100 is +25%.
Why aren't +50% and −50% the same?
Because the base changes: 100 + 50% = 150, but 150 − 50% = 75.