Six everyday percentage questions in one calculator: what is 15% of 200, what percent is 30 of 200, how much did a price rise or fall, what is a number plus or minus a percentage, and what was the price before a percentage was added. Pick the question, type two numbers and the calculator shows the answer and the working.
To find a percentage of a number, divide the percentage by 100 and multiply: 15% of 200 = 15 ÷ 100 × 200 = 30. Percentage change is (new − old) ÷ old × 100, so a rise from 50 to 75 is +50%.
Enter your numbers and press Calculate.
Results are rounded and depend on the values you enter. Double-check anything important.
How to use the Percentage calculator
- Choose the question you want answered from the list.
- Type the two numbers. A is usually the percentage or the starting value; the question in the list shows which is which.
- Press Calculate. The result shows the answer and the sum used to get it.
The formula
“Per cent” means “per hundred”, so every percentage question is really a fraction with 100 underneath. The hard part is usually knowing which number to divide by, and that is where most mistakes happen. The list of questions above is built to make that choice for you.
Worked examples
Percentage of a number: a 15% tip on a 200 bill is 15 ÷ 100 × 200 = 30. What percent: 30 correct answers out of 200 questions is 30 ÷ 200 × 100 = 15%. Change: a share price that moves from 50 to 75 has risen (75 − 50) ÷ 50 × 100 = +50%; moving back from 75 to 50 is a fall of 33.3333%, not 50%, because the starting value is now bigger.
Adding and removing a percentage
Shops, tax systems and salary reviews all add or remove percentages. Increasing 150 by 20% gives 150 × 1.2 = 180, and cutting 150 by 20% gives 150 × 0.8 = 120. Multiplying by a single factor like this is quicker than working out the percentage and then adding it, and it chains neatly: two rises of 10% are 1.1 × 1.1 = 1.21, a total rise of 21%, not 20%.
The reverse percentage trap
If a price of 180 already includes a 20% markup or tax, the original is not 180 minus 20%. Taking 20% off 180 gives 144, which is wrong. The right sum divides by the factor: 180 ÷ 1.2 = 150. This is the same maths a VAT calculator uses to strip tax out of a gross price. For example, Saudi VAT is 15%, so a receipt total of 115 contains 100 before VAT and 15 of tax. Our Saudi VAT calculator does that step for you.
Percent change or percent difference?
Use percent change when there is a clear before and after: last year and this year, the old price and the new price. Use percent difference when two values are simply being compared and neither is the starting point, such as two shops’ prices or two lab measurements. Percent difference divides by the average of the two numbers, so 10 and 20 are 66.6667% apart whichever order you type them in.
Percentage points
When a rate moves from 4% to 5%, it has risen by one percentage point, but by 25% in relative terms (1 ÷ 4 × 100). News reports about interest rates, polls and unemployment usually mean percentage points. If you put 4 and 5 into the percent change mode you get the relative figure, +25%.
FAQ
How do I work out a percentage of a number?
Divide the percentage by 100 and multiply by the number. 15% of 200 is 0.15 × 200 = 30.
How do I calculate percentage increase?
Subtract the old value from the new value, divide by the old value and multiply by 100. From 50 to 75 is (75 − 50) ÷ 50 × 100 = 50%.
How do I remove a percentage that was already added?
Divide by 1 plus the percentage as a decimal. A price of 180 that includes 20% was 180 ÷ 1.2 = 150 before it was added.
Why is a 50% rise followed by a 50% fall not back to the start?
The fall is worked out on the bigger number. 100 rises 50% to 150, and 50% of 150 is 75, so you end at 75.
Does the calculator store my numbers?
No. Everything is worked out in your browser and nothing is sent or saved.
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