How to use the percentage calculator
- Find the row that matches your question: a percentage of a number, what percent one number is of another, the change between two numbers, or a number increased or decreased by a percentage.
- Type your numbers into that row's boxes. The answer updates as you type.
- Copy the answer to paste it elsewhere.
Percentage formulas
| Question | Formula | Example |
|---|---|---|
| What is X% of Y? | Y × X ÷ 100 | 20% of 150 = 30 |
| X is what % of Y? | X ÷ Y × 100 | 30 of 150 = 20% |
| % change from X to Y | (Y − X) ÷ X × 100 | 50 to 75 = +50% |
| Increase Y by X% | Y × (1 + X ÷ 100) | 200 + 15% = 230 |
| Decrease Y by X% | Y × (1 − X ÷ 100) | 200 − 15% = 170 |
In plain words, a percentage is a number out of 100: 20% means 20 for every 100. Percentage change compares the difference with where you started, so it's divided by the starting value, not the new one. When the starting value is negative, the calculator divides by its size, so a rise still shows as positive.
Worked examples
- Exam marks: 432 out of 500 is 432 ÷ 500 × 100 = 86.4%.
- A salary hike: from ₹40,000 to ₹46,000 is (46,000 − 40,000) ÷ 40,000 × 100 = a 15% increase.
- A price rise: ₹1,200 increased by 8% is 1,200 × 1.08 = ₹1,296.
- Up then down: 100 increased by 10% is 110, and 110 decreased by 10% is 99, not 100.
Percent or percentage points?
When a percentage itself changes, say which change you mean. An interest rate moving from 3% to 5% has risen by 2 percentage points, but by 66.67% in relative terms. Enter 3 and 5 in the percentage change row to see the relative figure. For prices after a discount, thediscount calculator also handles stacked offers.
Common uses
- Working out exam marks. Enter the marks you scored and the maximum marks in the second row to get your percentage, for example 432 out of 500 is 86.4%.
- Salary hikes and price rises. Find the percentage change between your old and new salary, or work out a new price after a percentage increase.
- Tips, commissions and shares. Find a percentage of any amount, such as a 10% tip on a bill or a 2% commission on a sale.