# Percentage Calculator

URL: https://speedycalculator.com/calculators/math/percentage/
Last updated: 2026-10-25

> The percentage calculator finds P percent of a number by multiplying the number by P and dividing by 100. Type a result instead to work backwards and find what percentage one number is of another, so a single tool answers both common percentage questions.

## Inputs

- Percentage (%)
- Of number

## Results

- Result — Type a result to find what percent of the number it is.

## Formula

```
Result = P ÷ 100 × number
P = result ÷ number × 100
```

## Explanation

“Percent” means “per hundred”, so 15% is 15 out of every 100, or 0.15. Every percentage question is a version of the same equation with a different unknown.

### Two questions, one tool

- **What is 15% of 240?** Enter 15 and 240.
- **What percent of 240 is 36?** Enter 240, then type 36 in the result; the percentage is solved.

### Mental shortcut

Find 10% by moving the decimal point one place left, then scale: 15% is 10% plus half of 10%.

### Inputs explained

FieldWhat to enterPercentageIn %Of numberA number

### Example values

How the main result changes when **Percentage** changes and everything else stays at the example values above:

Percentage (%)Result7.51811.2527153618.754522.5543072

## Worked example

15% of 240 = 0.15 × 240 = **36**.

Reverse: 39.6 is 39.6 ÷ 240 × 100 = 16.5% of 240.

## Key terms

- **Percent**: A ratio expressed per hundred.
- **Base**: The number the percentage is taken of.
- **Percentage point**: The arithmetic difference between two percentages.

## FAQ

**Is X% of Y the same as Y% of X?**
Yes. 8% of 50 equals 50% of 8; both are 4.

**How do I add a percentage to a number?**
Multiply by (1 + P/100). Adding 20% to 50 gives 60.

**How do I find a percentage increase?**
Use the percentage change calculator.

**What formula does the Percentage Calculator use?**
Result = P ÷ 100 × number.

**Can I work backwards from the result?**
Yes. Type the result you want into Result and the calculator finds the matching percentage.


## Sources

- [NIST Guide for the Use of the International System of Units (SI), section 7.10.2](https://www.nist.gov/pml/special-publication-811)