What this calculator does
The Percentage Calculator answers the three percentage questions people ask most often. First, "what is X% of Y" — for example, what is 20% of 150. Second, "X is what percent of Y" — for example, 45 is what percent of 60. Third, "percentage change" — for example, if a price went from 80 to 100, by what percent did it rise?
It covers shopping discounts, tips and service charges, exam scores, tax and VAT, statistics, and price changes, and it works with whole numbers and decimals. You can also switch the page between English, Arabic, and Spanish.
How to use the Percentage Calculator
- Choose a mode from the list: "What is X% of Y?", "X is what percent of Y?", or "Percentage change from X to Y". The field labels update to match.
- Enter the first value in the first field (the percentage, the part, or the original value, depending on the mode).
- Enter the second value in the second field (the total, or the new value).
- Click "Calculate" to see the result below the button.
- Switch modes or change values and click again for a new answer.
Formulas
With X as the first value and Y as the second, the calculator uses:
The change formula divides by the absolute value of the original number, so going from 80 up to 100 gives +25% and going from 100 down to 80 gives −20%. Note that a rise and a fall of the same size do not cancel out to zero percent.
Examples
- What is 20% of 150? (20 ÷ 100) × 150 = 30 — a 20% discount on a 150 purchase saves you 30.
- 45 is what percent of 60? (45 ÷ 60) × 100 = 75% — a score of 45 out of 60 on a test.
- Percentage change from 80 to 100: ((100 − 80) ÷ 80) × 100 = +25% (increase).
Frequently asked questions
Can I use decimal numbers?
Yes. Values such as 12.75 or 0.5 work in every mode, and the result keeps up to six decimal places.
What is the difference between percent and percentage points?
Percent is a share of a whole, while percentage points describe the difference between two percentages. If a rate moves from 4% to 5%, it rose by 1 percentage point but by 25% in relative terms — use the change mode for the relative view.
Why does the change mode give +25% one way and −20% the other?
Because the change is always measured against the starting value. Going from 80 to 100 adds 20 on a base of 80 (+25%), while going from 100 to 80 removes 20 from a base of 100 (−20%).
Can the percentage be more than 100%?
Yes. If X is bigger than Y in the "what percent" mode, the result is above 100%, and a percentage above 100 in the first mode simply multiplies the number by more than one.
What about negative numbers?
They are supported. For example, the change from −50 to −40 is +20%, and −10% of 200 is −20. Just type the minus sign before the number.
Why can't I leave a needed field at zero?
Dividing by zero has no defined answer, so the "what percent" mode needs a non-zero total and the change mode needs a non-zero original value.
Is my data saved or sent anywhere?
No. Every calculation runs in your browser, and nothing you type is stored or sent to a server.
Related calculators
Other free calculators commonly used with this tool: Simple Arithmetic Calculator, Mortgage Calculator, and Loan EMI Calculator.
Want a deeper walkthrough? Read our percentage shortcuts guide.