Percentage Calculator
Three common percentage questions in one place. Type in the numbers and the answer updates as you go.
The three formulas
Percentage means "out of 100". These are the formulas behind the three calculators above.
Percentage of a number
Result = (percentage ÷ 100) × number
15% of 2,400 is 0.15 × 2,400 = 360.
One number as a percentage of another
Percentage = (part ÷ whole) × 100
45 out of 60 is 45 ÷ 60 × 100 = 75%.
Percentage change
Change = ((new − old) ÷ old) × 100
A price moving from 200 to 250 is a 25% increase. Going back from 250 to 200 is a 20% decrease. The two are not equal because the starting value differs.
Where people use it
- Working out a discount or the sale price of something
- Checking exam marks as a percentage
- Seeing how much a salary, price or investment has grown
- Splitting a bill or calculating a tip
Frequently asked questions
How do I calculate a discount?
Use the first calculator to find the discount amount (discount % of the price), then subtract it from the price. A 20% discount on 1,500 saves 300, so you pay 1,200.
Why is a 25% increase not reversed by a 25% decrease?
Because the second percentage applies to a bigger number. After going up 25% from 200 to 250, you need a 20% drop, not 25%, to get back to 200.
Can the result be more than 100%?
Yes. If the part is larger than the whole, or a value more than doubles, the percentage goes past 100.