Percentage Calculator
Find X% of a number, what percent one number is of another, percent change, and add or subtract a percentage.
X% of Y
X is what percent of Y?
Percent change from A to B
Increase or decrease by a percentage
How to calculate percentages
- 1
Pick the calculator
Use “X% of Y” for discounts and tips, “X is what % of Y” for shares and scores, “Percent change” for growth between two values, and “Increase or decrease” to apply a percentage to a value.
- 2
Enter the numbers
Type the two values. Both 1,234.5 and 1.234,5 are accepted, and a trailing % sign is ignored.
- 3
Read the result
The result updates as you type. The line under it shows the exact formula so you can check the calculation.
Percentage formulas with examples
The three basic formulas
X% of Y = Y × X ÷ 100. Example: 20% of 150 = 30. X as a percent of Y = X ÷ Y × 100. Example: 30 out of 150 = 20%. Percent change from A to B = (B − A) ÷ A × 100. Example: from 80 to 100 = +25%, from 100 to 80 = −20%. The same 20-unit gap gives a different percentage depending on which value you start from.
Adding and removing a percentage
Adding 10% multiplies by 1.10, subtracting 10% multiplies by 0.90. To reverse a percentage, divide instead of multiplying the other way. A price of 110 that already includes 10% tax has a net price of 110 ÷ 1.10 = 100. Subtracting 10% from 110 gives 99, which is off by one.
Percent vs. percentage points
When a value is itself a percentage, say which difference you mean. An interest rate moving from 4% to 5% is up 1 percentage point, or up 25% relative to 4%. Reports often mix these up.
Negative starting values
For a negative start, this calculator divides by the absolute value, so a loss shrinking from −50 to −25 shows as +50%. Some spreadsheets divide by the signed value and would show −50% for the same change.