Percentage Calculator

Use the percentage calculator for three common questions: finding a percentage of a value, expressing one number as a percentage of another, and measuring the percentage increase or decrease between two values.

The result includes the substituted formula so you can verify the arithmetic. Decimal and negative values are supported where the selected formula is defined.

How to use this calculator

1. Choose the percentage question you need to solve.
2. Enter values A and B.
3. Calculate and review the displayed formula.

Frequently asked questions

How do I calculate a percentage of a number?

Divide the percentage by 100, then multiply by the number.

How is percentage change calculated?

Subtract the original value from the new value, divide by the absolute original value, then multiply by 100.

Why can the original value not be zero?

Percentage change divides by the original value, so the standard formula is undefined when that value is zero.