Percentage Calculator
Find a percentage of a number, for example 15% of 240.
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Result:
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Calculation:
Use this calculator to answer the five most common percentage questions: what a percentage of a number is, what percent one number is of another, how to increase a number, how to apply a discount, and how much a value changed in percent. Pick the question, enter the two values and you get the result with every step shown.
Below you will find the formulas, one solved example for each case, a table of common percentages and answers to frequent questions.
How to use the percentage calculator?
Step 1: Pick the question you want to solve: % of a number, What % is, Increase, Discount or % change.
Step 2: Enter the two values. You can use a point or a comma for decimals, and you can also type the % sign, for example 12.5 or 12.5%.
Step 3: Press Calculate or the Enter key. The result shows in the right panel and updates when you change a value.
Step 4: The Calculation box shows the operations with your numbers.
Percentage formulas
A percentage is a fraction of 100: 15% means 15 out of every 100, so 15 ÷ 100 = 0.15. The five formulas of the calculator come from that idea.
| Question | Formula |
|---|---|
| What is p% of n? | result = p ÷ 100 × n |
| What percent is a of b? | percentage = a ÷ b × 100 |
| Increase n by p% | result = n + n × p ÷ 100 |
| Take p% off n | result = n - n × p ÷ 100 |
| Change from a to b | % change = (b - a) ÷ a × 100 |
Percentage examples
Example 1: What is 15% of 240?
Divide the percentage by 100 and multiply by the number:
15 ÷ 100 × 240 = 0.15 × 240 = 36
15% of 240 is 36.
Example 2: What percent is 18 of 72?
Divide the part by the whole and multiply by 100:
18 ÷ 72 × 100 = 0.25 × 100 = 25%
18 is 25% of 72.
Example 3: A $850 phone goes up 12%
First find the increase, then add it to the price:
Increase: 850 × 12 ÷ 100 = 102
New price: 850 + 102 = 952
The phone now costs $952.
Example 4: A $1200 coat with 25% off
Find the discount, then subtract it from the price:
Discount: 1200 × 25 ÷ 100 = 300
Final price: 1200 - 300 = 900
You save $300 and pay $900.
Example 5: Sales go from 80 to 100
Subtract the old value from the new one, divide by the old value and multiply by 100:
(100 - 80) ÷ 80 × 100 = 20 ÷ 80 × 100 = 25%
Sales rose 25%. If they fall from 100 back to 80, the change is 20 units, but in percent it is (80 - 100) ÷ 100 × 100 = -20%. The gap is the same size, but the base is different.
Common percentages table
| Percentage | Decimal | Fraction | Of 200 |
|---|---|---|---|
| 1% | 0.01 | 1/100 | 2 |
| 2% | 0.02 | 1/50 | 4 |
| 5% | 0.05 | 1/20 | 10 |
| 10% | 0.1 | 1/10 | 20 |
| 12.5% | 0.125 | 1/8 | 25 |
| 20% | 0.2 | 1/5 | 40 |
| 25% | 0.25 | 1/4 | 50 |
| 30% | 0.3 | 3/10 | 60 |
| 40% | 0.4 | 2/5 | 80 |
| 50% | 0.5 | 1/2 | 100 |
| 60% | 0.6 | 3/5 | 120 |
| 70% | 0.7 | 7/10 | 140 |
| 75% | 0.75 | 3/4 | 150 |
| 80% | 0.8 | 4/5 | 160 |
| 90% | 0.9 | 9/10 | 180 |
How to calculate percentages in your head
- 10%: move the decimal point one place to the left. 10% of 240 is 24.
- 1%: move it two places. 1% of 240 is 2.4.
- 50%: take half. 50% of 240 is 120.
- 25%: take half of half. 25% of 240 is 60.
- 5%: take half of 10%. 5% of 240 is 12.
- 15%: add 10% and 5%: 24 + 12 = 36.
Frequently asked questions
How do you calculate a percentage of a number?
Divide the percentage by 100 and multiply by the number. For example, 8% of 350 is 8 ÷ 100 × 350 = 28. You can also set it up as a rule of three: if 350 is 100%, what is 8%?
How do you convert a percentage to a decimal?
Divide by 100, or move the decimal point two places to the left. 45% is 0.45, 7% is 0.07 and 120% is 1.2.
Does a 20% increase followed by a 20% discount bring the price back?
No. If 100 goes up 20%, it becomes 120. A 20% discount on 120 takes off 24 and leaves 96. The second percentage applies to a different base, so they do not cancel out.
What is the difference between percent change and percentage points?
If a rate goes from 10% to 12%, it rises by 2 percentage points, which is the plain subtraction. The percent change is (12 - 10) ÷ 10 × 100 = 20%, because it is measured against the starting value.
Why can you not calculate a percent change from 0?
The formula divides by the starting value. If the starting value is 0, you would have to divide by 0, which has no result. In that case you can only say how much it changed in units.
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