Free online Percentage Calculator
Three simple steps
- Choose what you want to find: a percentage of a value, a part as a percentage, or a percentage change.
- Enter the two values shown by the selected mode.
- Read the answer and the arithmetic used to obtain it.
Understand your result
A percentage means “out of 100.” Choose the mode that matches your question; the same two numbers can answer different questions depending on the selected mode.
Which calculation should I choose?
| Your question | Inputs | Example |
|---|---|---|
| Find a percentage of a value | Percentage and full value | 20% of 150 = 30 |
| What percentage is this part? | Part and whole | 30 out of 150 = 20% |
| How much did it change? | Original and new value | 100 → 125 = +25% |
Worked example: a discount
For a price of 150 with 20% off, choose the first mode and enter 20 and 150. The discount is 30. Subtract it from the price: 150 − 30 = 120 to pay. The calculator’s first answer is the percentage amount, not automatically the final price.
How the formulas work
Percentage of a value: percentage ÷ 100 × value.
Part as a percentage: part ÷ whole × 100.
Percentage change: (new − original) ÷ |original| × 100. A positive answer is an increase; a negative answer is a decrease.
Common questions
Why can’t the whole or original value be zero?
Those modes divide by the whole or original value. Division by zero has no defined finite result.
Is a percentage change the same as percentage points?
No. A rate moving from 20% to 25% rises by 5 percentage points, but its relative increase is 25%.