Percentage Calculator: Four Common Percent Problems in One Place
Pick the question you have and fill in two or three numbers. The calculator finds a percentage of a value, tells you what percent one number is of another, measures percentage change between two values, or raises or lowers a number by a percentage.
Estimates only. Check important results before you rely on them.
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From related categoriesHow to use this calculator
- Choose the type of percentage problem from the first option.
- Fill in the numbers that appear. Only the fields for your choice are shown.
- Read the result at the top. The panel below it shows related figures such as the change or the multiplier.
- Use Share to send the exact numbers as a link.
The formula
Worked example
15% of 2,400 = 15 ÷ 100 × 2,400 = 360. Going from 80 to 100 is a (100 − 80) ÷ 80 × 100 = 25% increase. Raising 500 by 12% gives 500 × 1.12 = 560.
Understanding your result
The multiplier shows the same answer as a single number. A multiplier of 1.25 means a 25% increase and 0.8 means a 20% decrease. Note that a rise of 25% and a fall of 25% do not cancel out, because each is measured from a different starting value.
When to use it
- Work out discounts, tips, taxes and commissions.
- Check marks as a percentage of the total.
- Measure how a price, salary or traffic figure changed between two dates.
In-depth guide
The five common percentage questions
| Question | Formula | Example |
|---|---|---|
| What is X% of Y? | X ÷ 100 × Y | 15% of 2,400 = 360 |
| X is what percent of Y? | X ÷ Y × 100 | 45 of 60 = 75% |
| Percentage increase | (New − Old) ÷ Old × 100 | 80 to 100 = 25% |
| Percentage decrease | (Old − New) ÷ Old × 100 | 100 to 80 = 20% |
| Value after a change | Start × (1 ± X ÷ 100) | 500 + 12% = 560 |
Why +20% then −20% does not return to the start
A percentage always refers to the value it is applied to. Start with 100 and add 20% to get 120. A 20% fall from 120 is 24, which gives 96. The two changes are not equal in rupees, so they do not cancel out.
The table shows a few pairs of successive changes starting from 100.
| First change | Then | Result from 100 | Net change |
|---|---|---|---|
| +20% | -20% | 96.00 | -4.00% |
| +10% | +10% | 121.00 | +21.00% |
| +50% | -50% | 75.00 | -25.00% |
| -10% | -10% | 81.00 | -19.00% |
| +25% | -20% | 100.00 | +0.00% |
Percentage versus percentage points
If an interest rate moves from 6% to 8%, it has risen by 2 percentage points, but the rate itself is 33.3% higher in relative terms (2 ÷ 6). News and reports often mix these up, so check which one is meant.
Everyday uses
- Shop discounts, tips and tax on a bill.
- Marks and attendance.
- Salary hikes and price changes.
- Business margins, commissions and growth rates.
Tips for quick mental checks
- 10% of a number is the number divided by 10. Build other percentages from that: 5% is half of 10%, 15% is 10% plus 5%.
- X% of Y is the same as Y% of X, so use whichever is easier. For example 8% of 50 is the same as 50% of 8, which is 4.
- To check a percentage change, apply the result back to the old value and see if you reach the new value.
Assumptions and limits
Results are shown to up to four decimal places. Percentage change uses the absolute value of the old number, so the direction is shown by the label and the sign of the change. The old value cannot be zero.
Frequently asked questions
How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply by the number. For 15% of 2,400, that is 0.15 × 2,400 = 360.
How do I find what percent one number is of another?
Divide the part by the total and multiply by 100. 45 out of 180 is 45 ÷ 180 × 100 = 25%.
What is the difference between percentage change and percentage points?
Percentage change compares two values as a share of the old one. Percentage points are the plain subtraction of two percentages, so going from 10% to 12% is 2 points but a 20% change.
Why does a 50% increase followed by a 50% decrease not return to the start?
The decrease is taken from the larger new value. 100 becomes 150, and 50% of 150 is 75, so you end at 75.
Can the percentage be above 100?
Yes. 150% of 80 is 120. The calculator accepts large percentages for growth and markup problems.