Free tool
Percentage Calculator With the Working Shown for Every Answer
Nine common percent questions sit on one page, each with its own boxes and its own answer, so you can check a conversion rate, a price change or a sale without opening a spreadsheet. Under every result you will see the steps, which makes it easy to explain the number to someone else.
Percent of a number
Increase and decrease
Compare two numbers
Discount and tax
Press Enter to jump to the next box. Numbers can have commas, a currency sign or a % sign.
Every sum is worked out in your browser and nothing is sent anywhere. The numbers you type are remembered on your own device, and Copy link puts them in the part of the address after the hash sign, which does not travel to a server.
Start from the question you are really asking
Percent problems are confusing because the same words cover different sums. A site owner who sees traffic go from 4,000 to 5,200 visits wants a percent change. A shop owner pricing a sale wants a percent off. Someone reading a report that says a rate moved from 4% to 5% needs percentage points. This page keeps each of those as a separate row, so you pick the sentence that matches your question and type into the gaps.
The rows are grouped under four headings with a jump bar at the top: percent of a number, increase and decrease, comparing two numbers, and discount with tax. Each row is a sentence with blanks. For example, the first one reads What is 15% of 80, and the answer and its two steps appear beside it as soon as both boxes hold numbers.
What each row calculates
| Row | The sum |
|---|---|
| What is X% of Y | X divided by 100, then times Y |
| X is what % of Y | X divided by Y, then times 100 |
| X is P% of what | X divided by P as a fraction |
| Percent change from A to B | B minus A, divided by the size of A, times 100 |
| Number plus or minus a percent | The percent of the number is added or taken off |
| Number before a percent change | The final number divided by what remains of 100% |
| Percent difference | The gap between two numbers divided by their average |
| Percentage points | New rate minus old rate |
| Price with discounts and tax | Each discount applied in turn, then tax on the result |
Percentage points and percent change are different things
If a signup rate goes from 4% to 5%, it has risen by one percentage point. Measured against where it started, it has also grown by 25%. Both statements are true, and the row for rates shows both, so you can choose the wording that does not mislead. Reports that mix the two up are common, and the mix up makes small gains look huge or large gains look tiny.
- Use percentage points when you subtract one rate from another.
- Use percent change when you compare a new value with the old value as a share of the old one.
- Use percent difference when neither number is the original, such as two quotes from two suppliers.
Slips the page is built to catch
- Adding discounts together. A 25% discount followed by a further 10% off does not equal 35% off. The percentages multiply, and the answer tells you the single percent that matches both.
- Reversing a discount by adding it back. A price of 60 after a 25% cut was 80 before, not 75. The reverse row divides by what remained.
- Dividing by zero. A change from 0 has no percent, so the tool says so instead of showing nonsense.
- Typing symbols. Commas, currency signs and a percent sign are ignored, so 1,290 or 15% both read correctly.
Pressing Enter moves to the next box, and a Decimals menu sets how many places the answers may show, from 2 up to 10.
Using the numbers in a report
Every answer has its own Copy button that copies a plain sentence, such as the numbers and the result in words. The Copy link button saves the boxes you have changed into a web address, which is useful when you want to send someone the exact sum. When you are judging whether a change in conversions is worth acting on, our guide to website conversion optimization explains which numbers are worth watching. This page does the maths only and does not tell you what a good rate is. For money decisions, treat the results as plain arithmetic and not as advice.
Frequently asked questions
How do I work out a percent change?
Subtract the old number from the new one, divide by the old number, then multiply by 100. The Percent change row does all three steps and shows whether it is an increase or a decrease.
What is the difference between percent change and percent difference?
Percent change treats one number as the starting point. Percent difference compares two numbers against their average, so it gives the same answer whichever number comes first.
How do I find the original price before a discount?
Use the row that asks for the number after a percent decrease. It divides the sale price by what is left after the discount, which is why 60 after 25% off came from 80.
Are two discounts the same as one bigger one?
No. The second discount applies to the already reduced price. The discount row shows the single percent that equals both, which is always smaller than the two added together.
Can I type a percent sign or a dollar sign?
Yes. Spaces, commas, currency signs and the percent sign are stripped out before the sum, so you can paste numbers straight from a report.
Are my numbers saved?
They are kept on your own device so the page remembers them next time. The page has no server step at all.
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