How do I calculate a percentage increase?

Use the '% Change' mode. Enter the original value as 'From' and the new value as 'To'. The result shows the percentage increase (positive) or decrease (negative).

How do I find what percentage X is of Y?

Use the 'X is % of Y?' mode. For example, 30 is what percent of 150? The formula is (30 ÷ 150) × 100 = 20%.

How do I add a percentage to a value?

Use 'Add/Subtract %' mode, enter the base value and percentage, then click the + button. For VAT or tax: base = 100, % = 20, click + → result = 120.

Percentage Calculator

Runs in browser

4-mode percentage calculator: X% of Y, % change, add/subtract. Formula shown.

Free online percentage calculator with 4 modes: calculate X% of Y, find what percent X is of Y, compute percentage change between two values, and add or subtract a percentage. Shows formula with every result.

What is X% of Y?

Percentage (%)

Of (total value)

Result

20% × 150 = 30

🔒 Runs in your browser · No uploads · Your data never leaves your device

How to use

Choose a calculation mode
Select from 4 modes: 'X% of Y' for a percentage of a value, 'X is % of Y' to find the percentage, '% Change' for growth/decline, or 'Add/Subtract %' to apply a percentage.
Enter values
Fill in the input fields — the result and formula appear automatically as you type.
Read the formula
The formula line shows the exact calculation so you can verify or use it elsewhere.

Common use cases

Calculating discounts and tax — Add or subtract a VAT/tax percentage from a base price to get the final amount, with the formula shown.
Measuring growth rates — Calculate percentage change between two values to measure revenue growth, user growth, or performance improvement.

Examples

20% of 150
Select 'X% of Y', enter 20 and 150
Output
```
Result: 30 · Formula: 20% × 150 = 30
```
Price after 15% discount
Select 'Add/Subtract %', enter 200 base, 15%, press −
Output
```
Result: 170 · Formula: 200 − (15% of 200) = 170
```

Frequently asked questions

How do I calculate a percentage increase?: Use the '% Change' mode. Enter the original value as 'From' and the new value as 'To'. The result shows the percentage increase (positive) or decrease (negative).
How do I find what percentage X is of Y?: Use the 'X is % of Y?' mode. For example, 30 is what percent of 150? The formula is (30 ÷ 150) × 100 = 20%.
How do I add a percentage to a value?: Use 'Add/Subtract %' mode, enter the base value and percentage, then click the + button. For VAT or tax: base = 100, % = 20, click + → result = 120.

Key concepts

Percentage change: The relative difference between two values: ((new − old) / old) × 100. Positive = growth, negative = decline.
Base value: The starting value in a percentage calculation — the 'whole' from which a percentage is derived.

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