Percentage Calculator
Free percentage calculator: find X% of a number, what percent X is of Y, the percentage change between two values, or add and subtract a percentage.
Results
What is Percentage Calculator?
A calculator for the five everyday percentage questions: X% of Y, X is what percent of Y, percentage change from A to B, add X% to a value and subtract X% from a value. Each result shows the formula with your numbers so you can check it.
How to use Percentage Calculator
- Choose the calculation in Calculation.
- Enter the two numbers; the labels change to match the chosen calculation.
- Read the result and the formula below it. For percentage change the absolute difference and direction are shown too.
Example
Percentage change from 80 to 100
25% (difference 20, increase)
(100 − 80) ÷ 80 × 100 = 25
When to use Percentage Calculator
Use it for discounts, tax shares, grade percentages, price changes or growth rates. For several discounts applied one after another use the Discount Calculator, and for profit margin versus markup use the Margin Calculator, because those are not simple single percentages.
How Percentage Calculator works
The tool applies one formula per mode: X% of Y = X ÷ 100 × Y; X as a percent of Y = X ÷ Y × 100; percentage change = (B − A) ÷ |A| × 100; adding X% = Y × (1 + X ÷ 100); subtracting X% = Y × (1 − X ÷ 100). Results are shown with up to 6 decimals in your language's number format. Division by zero (a whole of 0, or a change from 0) shows an error instead of a meaningless number. You may type decimals with a dot or a comma.
Common Use Cases
- Working out 15% of a bill or a budget
- Finding what share of a total one part represents
- Measuring the percentage change of a price, salary or metric
- Adding VAT-style surcharges or removing a fixed percentage
FAQs
Why is a 20% decrease followed by a 20% increase not back to the start?
Each percentage applies to a different base. 100 − 20% = 80, and 80 + 20% = 96. To undo a 20% decrease you need a 25% increase.
How is percentage change different from percentage points?
Going from 10% to 12% is a change of 2 percentage points but a 20% percentage change, because (12 − 10) ÷ 10 = 0.2.
What happens if the old value is negative?
The change is divided by the absolute value of the old value, so moving from −50 to −25 is reported as a 50% increase.