Percentage Calculator
This percentage calculator works out percents the easy way and shows you the steps, so it makes sense. Pick what you want: a percent of a number, what percent one number is of another, the total behind a percent, a percentage change, or even a percent of a percent. Type your numbers and the answer updates as you go, with a simple bar that shows the percentage at a glance. It's built so anyone can calculate a percentage in seconds.
- 5 simple modes
- Steps shown
- Live percent bar
- Percent change
- Percent of a percent
Last updated June 16, 2026 Formula: number × percent ÷ 100 Reviewed by the Calcowa math team
Enter numbers to see the answer.
80 × 15 ÷ 100 = 12
What is a percentage?
A percentage is a number out of 100. The word "per cent" literally means "per hundred", so 25% is the same as 25 out of 100, or the fraction 25/100, or the decimal 0.25. That's the whole idea, and it's why percentages make different amounts easy to compare.
The main percentage formula is short: a percent of a number equals the number times the percent, divided by 100. Write it as number × percent ÷ 100, and you'll solve almost any everyday percentage question with it.
How do you calculate a percentage?
To calculate a percent of a number, multiply and then divide by 100. Here's how it goes for 20% of 50:
- 1
Write the percent and the numberYou want 20% of 50, so the percent is 20 and the number is 50.
- 2
Multiply them50 × 20 = 1,000.
- 3
Divide by 1001,000 ÷ 100 = 10, so 20% of 50 is 10.
Handy shortcut: 10% is the number with its decimal point moved one spot to the left, so 10% of 50 is 5. Double it for 20%, halve it for 5%.
How to find the percentage of a number
This is the most common one, like working out a tip or a sale price, and it's the mode you'll reach for most. To find the percentage of a number, multiply the number by the percent and divide by 100. So 15% of 80 is 80 × 15 ÷ 100 = 12. Use the "% of a number" mode above, type the percent and the number, and you'll see the answer and the steps at once.
What percent is one number of another?
When you want to know what percent one number is of another, divide the part by the whole and multiply by 100. A test score of 45 out of 60 is 45 ÷ 60 × 100 = 75%. That's how you turn marks, hits, or any "this out of that" into a percent. Pick the "Find the %" mode and enter the two numbers.
If a number is a percent, what's the total?
Sometimes you know the part and the percent, but not the whole. To find the total, divide the number by the percent written as a decimal. If 10 is 20% of a total, then the total is 10 ÷ 0.20 = 50. It's handy for working backward from a deposit, a tax, or a tip to the original amount. The "Find the total" mode does the reverse percent for you.
Percentage of a percentage
A percentage of a percentage trips a lot of people up. You take a percent of another percent by multiplying them and dividing by 100, so 50% of 20% is 50 × 20 ÷ 100 = 10%. This matters with stacked discounts: 20% off followed by another 50% off isn't 70% off, because the second cut applies to the already-lower price. The "% of a %" mode does this for you.
Percentage change, increase, and decrease
Percentage change tells you how much a number went up or down compared to where it started. The formula is (new − old) ÷ old × 100. If a price rose from 50 to 75, that's (75 − 50) ÷ 50 × 100 = 50% increase. If it dropped, the answer is negative and you call it a decrease. The "% change" mode above labels it and shows the sign, so you don't have to remember which is which. For a dedicated tool with a raise-by-a-percent option, see the percentage increase calculator.
Percent, decimal, and fraction
A percent, a decimal, and a fraction are three ways to write the same value. Divide a percent by 100 to get the decimal, or put it over 100 and simplify to get the fraction. These are the everyday ones you'll want to know by heart.
| Percent | Decimal | Fraction |
|---|---|---|
| 10% | 0.10 | 1/10 |
| 20% | 0.20 | 1/5 |
| 25% | 0.25 | 1/4 |
| 50% | 0.50 | 1/2 |
| 75% | 0.75 | 3/4 |
Common percentage examples
| Question | Answer |
|---|---|
| 10% of 50 | 5 |
| 20% of 200 | 40 |
| 15% of 80 | 12 (a common tip) |
| 25% of 60 | 15 |
| What % is 30 of 120 | 25% |
Frequently asked questions
Is a percent the same as a fraction out of 100?
Yes. A percent is simply a fraction with 100 on the bottom, so 40% is 40/100. That's why you divide by 100 to use it, and it's the one fact that makes every other percentage rule click.
To find a percent of a number, multiply the number by the percent and divide by 100. So 15% of 80 is 80 × 15 ÷ 100 = 12. To find what percent one number is of another, divide the first by the second and multiply by 100, like 30 ÷ 120 × 100 = 25%.
The main one is: percent of a number = number × percent ÷ 100. To go the other way, percent = part ÷ whole × 100. Both come from the idea that "per cent" means "per hundred", so a percent is just a fraction out of 100.
Multiply the number by the percent, then divide by 100. For 20% of 50, that's 50 × 20 ÷ 100 = 10. A quick trick: 10% is just the number with the decimal moved one place left, so 10% of 50 is 5, and you can scale from there.
Divide the part by the whole, then multiply by 100. If you scored 45 out of 60 on a test, that's 45 ÷ 60 × 100 = 75%. Pick the "Find the %" mode above and it does it for you.
It's taking a percent of another percent, which you work out by multiplying them and dividing by 100. So 50% of 20% is 50 × 20 ÷ 100 = 10%. This comes up with stacked discounts, where 20% off and then another 50% off isn't 70% off.
Divide the percent by 100 to get the decimal, so 25% is 0.25. For the fraction, put the percent over 100 and simplify, so 25% is 25/100, which reduces to 1/4. The table on this page lists the everyday ones.
Both measure change from a starting number. An increase means the new value is higher, a decrease means it's lower, and the formula is the same: (new − old) ÷ old × 100. The "% change" mode above labels it for you and shows the sign.
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