Percentage Calculator
What is X% of Y?
What is X% of Y? result:
Enter both numbers to see the answer.
X is what percent of Y?
X is what percent of Y? result:
Enter both numbers to see the answer.
Percentage increase or decrease
Percentage increase or decrease result:
Enter both numbers to see the answer.
X is Y% of what?
X is Y% of what? result:
Enter both numbers to see the answer.
Percentage difference between two numbers
Percentage difference between two numbers result:
Enter both numbers to see the answer.
How to use the Percentage Calculator
- Pick the question that matches yours. Each calculator answers one kind of percentage problem.
- Type your two numbers. The answer and the working appear instantly.
- Use Copy to copy the answer. Commas, decimals, negative numbers and a trailing % sign are all fine.
Examples
- What is 20% of 150? 0.2 × 150 = 30.
- A $45 meal with an 18% tip: 18% of 45 = 8.10, so the total is $53.10.
- 30 out of 150 questions right: 30 ÷ 150 × 100 = 20%.
- Rent goes from $1,200 to $1,320: (1,320 − 1,200) ÷ 1,200 × 100 = a 10% increase.
- A share price falls from 80 to 60: (60 − 80) ÷ 80 × 100 = a 25% decrease.
- $30 is a 20% deposit. What is the full price? 30 ÷ 0.2 = $150.
Percentage formulas
“Per cent” means “per hundred”, so 20% is 20 ÷ 100 = 0.2. Every formula below comes from that one idea.
- X% of Y = X ÷ 100 × Y. Percentages are reversible, so 20% of 150 equals 150% of 20.
- X as a percentage of Y = X ÷ Y × 100.
- Percentage change = (new − old) ÷ old × 100. A positive result is an increase and a negative one is a decrease.
- The whole, when X is Y% of it = X ÷ (Y ÷ 100).
- Percentage difference = |A − B| ÷ ((A + B) ÷ 2) × 100. Use it to compare two values when neither one is the starting point.
Increases and decreases are not symmetric
Going from 50 to 75 is a 50% increase, but going back from 75 to 50 is a 33.3% decrease, because each change is measured against a different starting value. In the same way, a 50% fall followed by a 50% rise leaves you at 75% of where you started, not 100%.
Percent vs percentage points
If an interest rate moves from 4% to 5%, it has risen by 1 percentage point, but by 25% in relative terms. Use percentage points for the gap between two percentages, and the percentage change calculator for the relative change.
Frequently asked questions
How do I calculate a percentage of a number in my head?
Find 10% by moving the decimal point one place left, then scale it. For 15% of 80: 10% is 8, 5% is half of that (4), so 15% is 12. For 1%, move the decimal point two places.
How do I add or subtract a percentage?
Multiply by 1 plus or minus the percentage as a decimal. Adding 20% to 50 is 50 × 1.2 = 60. Taking 20% off 50 is 50 × 0.8 = 40.
Why can't I calculate a percentage change from zero?
Percentage change divides by the starting value, and dividing by zero is undefined. Any rise from zero would be an infinite percentage, so describe it as an absolute change instead, for example “up from 0 to 12”.
What is the difference between percentage change and percentage difference?
Percentage change has a direction: it compares a new value with an old one. Percentage difference has no starting point: it compares two values against their average, so swapping them gives the same answer.
Can a percentage be more than 100%?
Yes. 150 is 300% of 50, and a price that triples has risen by 200%. Only a share of a whole, such as a test score or a slice of a pie chart, is limited to 100%.
How are the answers rounded?
Answers show up to 6 decimal places, with trailing zeros removed. Round the copied value to whatever precision you need, such as 2 decimal places for money.
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