How to calculate a percentage
Turn “percent of” into a multiplication by moving the decimal, and keep the whole amount in view.
Short answer
Write the percent as a decimal by dividing by 100, then multiply by the whole amount. Twenty percent of 150 is 0.20 × 150 = 30.
From words to one product
“Percent” means per hundred. Dividing by 100 is the whole translation. 7% is 0.07. 7.5% is 0.075. Multiply that decimal by the amount the percent applies to. If you are going the other way — a part back to a percent — divide the part by the whole and then multiply by 100.
Keep the units. Twenty percent of $150 is $30, not 30 percent. If the whole is zero, a “what percent is this” question has no answer, because you would be dividing by zero.
Practical steps
- Divide the percent by 100.
- Multiply by the whole.
- Label the result with the unit of the whole.
Common mistakes
- Moving the decimal the wrong way and turning 5% into 5.
Frequently asked questions
- Is a percentage point the same as a percent?
- No. A change from 5% to 7% is 2 percentage points, which is a 40% increase relative to 5.
Related
- Percentage calculatorFind a percent of a number, what percent one number is of another, the change between two values, or a discount.
- How to calculate percent changeCompare two numbers as a percent of the starting value, and do not divide by the ending value.
- How to round moneyRound a currency result to the cent at the end, and avoid rounding the inputs first.