How to use the percentage calculator
- Choose the type of percentage calculation you need.
- Enter the two values in the labeled fields.
- Select Calculate to see the answer and a plain-language explanation.
- Copy or share the result if you need it elsewhere.
Percentage formulas
Find a percentage of a value
Result = value × percentage ÷ 100
To find 20% of 500, multiply 500 by 20 and divide by 100. The result is 100.
Find what percentage one number is of another
Percentage = first value ÷ comparison value × 100
If 50 out of 200 items are complete, 50 ÷ 200 × 100 equals 25%.
Increase or decrease by a percentage
New value = original value × (1 ± percentage ÷ 100)
Use plus for an increase and minus for a decrease.
Worked examples
15% of 80
80 × 15 ÷ 100 = 12
30 is what % of 120?
30 ÷ 120 × 100 = 25%
Increase 250 by 8%
250 × 1.08 = 270
Decrease 90 by 20%
90 × 0.80 = 72
Frequently asked questions
What is 20% of 500?
20% of 500 is 100. Multiply 500 by 0.20.
How do I calculate a percentage increase?
Subtract the original value from the new value, divide that difference by the original value, then multiply by 100.
Can a percentage be greater than 100?
Yes. A percentage above 100 means the measured amount is greater than the full reference amount.
Why might my manual answer look slightly different?
Rounding at different stages can change the final displayed digits. This calculator keeps full precision during calculation and rounds only for display.