# Percentage calculator

URL: https://shahid09.is-a.dev/tools/percentage-calculator/
Author: Muhammad Shahid (https://shahid09.is-a.dev/)
Free tool · runs in your browser

Work out a percentage of a number, what percent one number is of another, or the percentage change from one number to another.

**Quick answer:** Three calculators in one: X% of Y is X ÷ 100 × Y (15% of 80 = 12); X is what % of Y is X ÷ Y × 100 (30 of 120 = 25%); and percentage change from A to B is (B − A) ÷ A × 100 (50 to 65 = +30%). Results update as you type, and decimals and negative numbers work.

## How to use it

1. **Pick the question.** X% of a number, what percent one number is of another, or the change between two numbers.
2. **Type the two numbers.** Decimals with a dot or comma both work.
3. **Read the answer.** The result appears at once next to the question.

## Example

The three calculators with sample numbers:

Input:

```
What is 15% of 80?
30 is what % of 120?
From 50 to 65?
```

Output:

```
= 12
= 25%
= +30%
```

## Common errors and how to fix them

- **Two discounts were added together**: 20% and then 10% off is 28% off, not 30%, because the second applies to the reduced price.
- **Percent and percentage points were mixed up**: Going from 5% to 7% is 2 percentage points, or a 40% increase. Say which one you mean.
- **A 50% fall and 50% rise did not cancel out**: The rise is on the smaller number: 100 → 50 → 75. To get back to 100, you need a 100% rise.
- **The change from 0 shows a dash**: Percentage change from zero is undefined. Report the absolute change instead.

## Frequently asked questions

### How do I calculate a percentage of a number?

Divide the percentage by 100 and multiply by the number: 15% of 80 is 0.15 × 80 = 12.

### How do I find what percent one number is of another?

Divide the part by the whole and multiply by 100: 30 out of 120 is 30 ÷ 120 × 100 = 25%.

### How do I calculate percentage increase?

Subtract the old value from the new one, divide by the old value and multiply by 100: from 50 to 65 is 15 ÷ 50 × 100 = +30%.

### How do I calculate a discount?

Multiply the price by the discount and subtract it: 20% off 250 is 250 − 50 = 200. Or multiply by 0.8 directly.

### Are two discounts of 20% and 10% the same as 30%?

No. They apply one after another: 100 × 0.8 × 0.9 = 72, which is 28% off.

### What is the difference between percent and percentage points?

A rate rising from 5% to 7% rises by 2 percentage points but by 40 percent.

### Why does a 50% drop and a 50% rise not cancel out?

The rise is calculated on the smaller number: 100 drops to 50, and 50% of 50 brings it only to 75.

### How do I add VAT or tax?

Multiply by 1 plus the rate: 100 plus 17% VAT is 100 × 1.17 = 117.

### How do I reverse a percentage?

Divide by 1 plus the rate: a price of 117 including 17% tax was 117 ÷ 1.17 = 100 before tax.

### Why is percentage change from zero not shown?

Any change from zero is an infinite percentage, so it cannot be calculated. Report the absolute change instead.

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