Percentage calculator
Answer every everyday percent question, from discounts to raises, with the working shown.
20% of 65
13
Steps
- 20 ÷ 100 = 0.2
- 0.2 × 65 = 13
How to use the percentage calculator
- Choose the question you want to answer.
- Fill in the two numbers.
- Read the answer and the step-by-step working below it.
About this calculator
Percent means “per hundred”. Almost every everyday question is one of three: what is X% of a number, what percent is one number of another, and by what percent did something change. The calculator has a mode for each.
Percentage change is the one people most often get wrong: always divide by the original value, not the new one. The steps shown under each answer make the method easy to check.
The three formulas
X% of Y = X ÷ 100 × Y · X is ?% of Y = X ÷ Y × 100 · Change = (New − Old) ÷ Old × 100
A positive change is an increase, a negative one a decrease.
Example
20% of $65 is $13, so a 20% discount brings the price to $52. A rent rise from $1,500 to $1,620 is a (1,620 − 1,500) ÷ 1,500 × 100 = 8% increase.
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. 15% of 80 is 80 × 15 ÷ 100 = 12.
How do I calculate percentage increase?
Subtract the old value from the new one, divide by the old value and multiply by 100. From 50 to 65 is (65 − 50) ÷ 50 × 100 = 30%.
What is the difference between percent and percentage points?
If a rate rises from 4% to 5%, it went up 1 percentage point, which is a 25% increase relative to 4%. Use points for differences between rates.
How do I reverse a percentage, finding the original price?
Divide the final value by (1 + rate). A price of $120 after a 20% markup was 120 ÷ 1.2 = $100. After a 20% discount it was 120 ÷ 0.8 = $150.