How do I work out a percentage?
Find a percentage of a number, or what percent one number is of another, as you type.
- Is
- 43.2
18% of 240 is 43.2.
- The number plus the percent
- 283.2
- The number minus the percent
- 196.8
Is: 43.2. 18% of 240 is 43.2.
How to calculate
Computes a percentage of a number, what percent one number is of another, or the whole number from a part and a percent.
Example with the default inputs (Percent 18%, Of 240): 18% of 240 is 43.2.
Formula: R = P ÷ 100 × V: the part R is P percent of the whole number V.
- Percentages are in percent points: 18 means 18%.
- Solving for the percent or the whole number divides by the other one, so there is no answer when it is 0.
Worked examples
Each example is checked against the calculator on every build.
- Percent 18%, Of 240 gives Is 43.2, The number plus the percent 283.2, The number minus the percent 196.8.Source: OpenStax, Prealgebra 2e, §6.2 Solve General Applications of Percent. https://openstax.org/books/prealgebra-2e/pages/6-2-solve-general-applications-of-percent
- Is 43.2, Of 240 gives Percent 18%.Source: OpenStax, Prealgebra 2e, §6.2 Solve General Applications of Percent. https://openstax.org/books/prealgebra-2e/pages/6-2-solve-general-applications-of-percent
- Percent 25%, Is 15 gives Of 60.Source: OpenStax, Prealgebra 2e, §6.2 Solve General Applications of Percent. https://openstax.org/books/prealgebra-2e/pages/6-2-solve-general-applications-of-percent
How it works
Fill in any two of the three numbers and the calculator finds the third. The formula is:
R = P ÷ 100 × V
where P is the percent, V is the whole number and R is the part.
- R = P ÷ 100 × V (18% of 240 is 43.2)
- P = R ÷ V × 100 (43.2 is 18% of 240)
- V = R ÷ P × 100 (43.2 is 18% of 240, so the whole is 240)
It also shows the number plus and minus the percent: V + R and V − R.
For a percentage change from A to B, the formula is (B − A) ÷ A × 100, as in the questions below.
Assumptions
- Percentages are in percent points: type 18 for 18%.
- Solving for the percent divides by the whole number, and solving for the whole number divides by the percent, so there is no answer when that number is 0.
Worked examples by hand
18% of 240. 18 ÷ 100 × 240 = 0.18 × 240 = 43.2. Adding it gives 240 + 43.2 = 283.2; taking it off gives 240 − 43.2 = 196.8.
What percent is 43.2 of 240? 43.2 ÷ 240 × 100 = 18%.
What is 15 25% of? 15 ÷ 25 × 100 = 60.
Other questions people ask
How do I calculate a percentage?
To calculate a percentage, divide the part by the whole and multiply by 100. For example, if you have 25 out of 100, the percentage is (25 ÷ 100) × 100 = 25%. The formula is: Percentage = (Part ÷ Whole) × 100.
How do I calculate percentage increase?
To calculate percentage increase, subtract the original value from the new value, divide by the original value, and multiply by 100. Formula: ((New Value - Original Value) ÷ Original Value) × 100. For example, if a price increases from $100 to $120, the percentage increase is ((120 - 100) ÷ 100) × 100 = 20%.
How do I calculate percentage decrease?
To calculate percentage decrease, subtract the new value from the original value, divide by the original value, and multiply by 100. Formula: ((Original Value - New Value) ÷ Original Value) × 100. For example, if a price decreases from $100 to $80, the percentage decrease is ((100 - 80) ÷ 100) × 100 = 20%.
What is the difference between percentage and percentage points?
A percentage is a ratio expressed as a fraction of 100. Percentage points are the difference between two percentages. For example, if interest rates increase from 5% to 7%, that's a 2 percentage point increase, or a 40% increase relative to the original rate. Percentage points are absolute differences, while percentages can be relative changes.
How do I convert a decimal to a percentage?
To convert a decimal to a percentage, multiply by 100. For example, 0.25 becomes 25%, 0.75 becomes 75%, and 1.5 becomes 150%. You can also move the decimal point two places to the right and add the % symbol.
How do I convert a percentage to a decimal?
To convert a percentage to a decimal, divide by 100. For example, 25% becomes 0.25, 75% becomes 0.75, and 150% becomes 1.5. You can also move the decimal point two places to the left and remove the % symbol.
How do I calculate what percentage one number is of another?
To find what percentage one number is of another, divide the first number by the second number and multiply by 100. For example, if 15 is what percentage of 60, the calculation is (15 ÷ 60) × 100 = 25%. So 15 is 25% of 60.
How do I add or subtract percentages?
To add or subtract percentages, first convert them to decimals, perform the calculation, then convert back to a percentage. For example, 25% + 15% = 0.25 + 0.15 = 0.40 = 40%. However, be careful with percentage changes - a 10% increase followed by a 10% decrease doesn't return to the original value.
What is compound percentage growth?
Compound percentage growth occurs when a percentage change is applied repeatedly to the new value each time. For example, if an investment grows 10% each year, after 2 years it grows by 21% (not 20%) because the second year's 10% is calculated on the new higher value.
How do I calculate percentage of total?
To calculate the percentage of total, divide the specific value by the total value and multiply by 100. For example, if you spent $30 out of a $100 budget, the percentage of total is (30 ÷ 100) × 100 = 30%. This shows what portion of the total the specific value represents.
Why doesn’t a 25% rise and then a 25% fall get me back?
Because the fall is taken from the bigger number. 240 up 25% is 300, and 300 down 25% is 225. To get back to 240 from 300 you need a 20% fall.