Four questions. Clear answers.
Percentage
calculators.
Find a percentage, compare two values, calculate a discount or recover an original price.
Each calculator is ready to use, with its formula and an example below.
Percentage of a number
What is X% of a number?
How to calculate it
Multiply the percentage by the number, then divide by 100. For example, 20% of 150 = 20 × 150 ÷ 100 = 30.
A percentage means “per hundred”: 50% is one half and 200% is twice the original number. This calculator also accepts decimal percentages.
Percentage change calculator
Calculate a percentage increase or decrease.
How to calculate it
Subtract the original value from the new value, divide by the original, then multiply by 100. Going from 80 to 100 is a 25% increase; going from 100 to 80 is a 20% decrease.
The original value must be greater than zero. Reversing a change does not usually give the same percentage because the starting value changes. A move from 20% to 25% is a 25% relative increase, but a difference of 5 percentage points.
Discount calculator
Find the price after a percentage discount.
How to calculate it
A 20% discount on 100 saves 20 and leaves a price of 80. Enter the price and the percentage off to calculate the reduced price.
Use a non-negative price and a discount from 0 to 100%. A 100% discount makes the price zero. These calculations exclude taxes, shipping and currency-specific rounding.
Original price calculator
Find the price before a percentage discount.
How to calculate it
If the sale price is 80 after a 20% discount, divide 80 by 0.8 to recover the original price of 100. Adding 20% to 80 would give 96, which does not undo the discount.
The discount must be at least 0% and less than 100%. At 100% off, every original price becomes zero, so the original price cannot be recovered from the discounted price alone.
Worked examples
- What is 5% of 430?
- What is 20% of 150?
- What is the percentage change from 80 to 100?
- What is 20% off 100?
- What was the original price before 20% off, if the sale price is 80?
No account is required. Interactive calculations run in your browser. Opening a calculation page sends the numbers in its URL to our server to render the answer. Rounded results use ≈ and up to 12 significant digits; use consistent units for both prices or values.
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