Percentage Calculator
Work out what X% of a number is, what percentage one number is of another, and the percentage difference between two values.
- Category
- Calculators
- Updated
- Cost
- Free · no sign-up
Result
12.6
15% of 84
15 ÷ 100 × 84 = 12.6
Three questions, one calculator
Almost every percentage problem is one of three questions, and this calculator handles each in its own mode.
What is X% of Y? Multiply Y by X ÷ 100. A 15% tip on 84 is 0.15 × 84 = 12.60.
X is what percent of Y? Divide X by Y and multiply by 100. If 37 of 120 seats are taken, that's 37 ÷ 120 × 100 = 30.8%.
What's the percentage change from X to Y? Subtract, divide by the original value, multiply by 100. From 120 to 150 is (150 − 120) ÷ 120 × 100 = 25%.
Percent versus percentage points
This distinction causes more reporting errors than any other. If an interest rate moves from 4% to 5%, that is:
- an increase of 1 percentage point
- an increase of 25 percent
Both are correct. Which one you use changes how big the change sounds, so state which you mean whenever the difference matters.
Doing it in your head
A few shortcuts cover most everyday cases:
- 10% — move the decimal one place left.
- 5% — half of 10%.
- 20% — double 10%.
- 15% — 10% plus half of it.
- 1% — move the decimal two places left.
Percentages are also commutative: 8% of 50 equals 50% of 8, which is 4. Swapping the numbers sometimes turns an awkward sum into an obvious one.
How to use the Percentage Calculator
Three steps, no sign-up.
Pick the question you're asking
Three modes: percent of a number, one number as a percent of another, and percentage change.
Fill in the two values
The result updates as you type — there's nothing to submit.
Check the working
Each mode shows the equation it used, so you can reuse it by hand.
Worked examples
A 15% tip on a $84 bill
- Inputs
- 15% of 84
- Result
- 12.60