Percentage Calculator
Find X% of a number, what percent one number is of another, percentage increase or decrease, and add or subtract a percentage.
How to use Percentage Calculator
- Choose the type of calculation.
- Enter your two numbers — decimals and negatives are allowed.
- The result and formula update as you type. Use Reset to start again.
Frequently asked questions
How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply by the number. For example, 20% of 150 is 0.20 × 150 = 30.
Why is a 50% increase followed by a 50% decrease not the original value?
Each percentage is applied to a different starting value. 100 + 50% = 150, but 150 − 50% = 75, because the second 50% is taken from 150, not 100.
What is the difference between percentage and percentage points?
If an interest rate goes from 4% to 5%, it rose by 1 percentage point, but by 25% in relative terms, because 1 is 25% of 4.
Why can't I calculate percentage change from zero?
Percentage change divides by the original value. Dividing by zero is undefined, so no meaningful percentage exists — the calculator shows a message instead of a misleading number.
How are negative numbers handled?
Percentage change divides by the absolute (positive) size of the original value, so going from −50 to −25 is reported as a 50% increase.
Are my numbers sent anywhere?
No. All calculations happen in your browser and nothing is sent to a server.
Worked examples
- What is 20% of 150?
- (20 ÷ 100) × 150 = 30
- 30 is what percent of 150?
- (30 ÷ 150) × 100 = 20%
- A price rises from ₹50 to ₹75. What is the increase?
- ((75 − 50) ÷ 50) × 100 = 50% increase
- A score drops from 80 to 60. What is the decrease?
- ((80 − 60) ÷ 80) × 100 = 25% decrease
- Add 18% tax to 200.
- 200 × (1 + 0.18) = 236
- Take 15% off 1,200.
- 1,200 × (1 − 0.15) = 1,020
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