What is the Percentage Calculator?
Percentages turn up everywhere: marks in an exam, a salary hike, a price rise, a discount, a tax or a change in sales. This page has a small calculator for each common question, and all of them update as you type.
Each result also shows the formula with your numbers in it, so you can check the working or learn how to do it by hand.
How to use it
- Find the question that matches yours, such as “What is X% of Y?” or “Percentage change from X to Y”.
- Type your numbers into that row.
- Read the answer and the working below it.
Example
Percentage change from 80 to 100
25% increase · (100 − 80) ÷ 80 × 100 = 25
Features
- Six calculators in one. Percent of, what percent, change, difference, increase/decrease and reverse percentage.
- Shows the working. Every answer includes the formula with your numbers.
- Marks to percentage. Turn exam marks into a percentage in one step.
- Reverse percentage. Find the original price before a markup, tax or discount.
- Live results. Answers update as you type; no button to press.
- Precise. Results to up to 4 decimal places, without rounding errors piling up.
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. For example, 18% of 2,500 is 2,500 × 18 ÷ 100 = 450.
How do I convert marks into a percentage?
Divide the marks you scored by the total marks and multiply by 100. For 452 out of 500, that is 452 ÷ 500 × 100 = 90.4%. Use “X is what percent of Y”.
What is the difference between percentage change and percentage difference?
Percentage change compares a new value with an old one, so direction matters (80 to 100 is +25%, 100 to 80 is −20%). Percentage difference compares two values without a before and after, relative to their average (22.22% for 80 and 100).
How do I find the original price before a percentage increase?
Divide the final value by 1 plus the percentage ÷ 100. If a price is ₹1,180 after an 18% increase, the original was 1,180 ÷ 1.18 = ₹1,000. Use the reverse percentage calculator.
Why does a 10% rise followed by a 10% fall not get me back to the start?
The second 10% is taken from a bigger number. 100 + 10% = 110, and 110 − 10% = 99. Percentages apply to the current value, not the original.
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