Percentage Calculator
Percent of a value, proportions, change and increase/decrease — pick a tab below.
What is a percent?
A percent is a fraction of 100 — "per cent" literally means "per hundred". 20% means 20 out of every 100, or 0.20 as a decimal. Percentages let you compare quantities of very different sizes on the same simple scale.
How to calculate a percentage of a value
Divide the percentage by 100, then multiply by the value.
Example: 20% of 150 → (20 / 100) × 150 = 30.
Percentage change
Take the difference between the new and original value, divide by the original value, then multiply by 100. A positive result is an increase, a negative result is a decrease.
Example: from 100 to 125 → ((125 − 100) / 100) × 100 = +25%.
Increasing or decreasing a value by a percent
Work out the percentage of the base value first, then add it (increase) or subtract it (decrease).
Example: 150 increased by 20% → 150 + 30 = 180. Decreased by 20% → 150 − 30 = 120.
Examples
- Sales tax: 8% of a $64 bill is $5.12.
- Exam score: 342 out of 500 is 68.4%.
- Pay rise: a salary going from $50,000 to $54,500 is a +9% change.
- Discount: a $90 jacket reduced by 30% costs $63.
Frequently asked questions
Divide the percentage by 100 and multiply by the number. For 20% of 150: (20 / 100) × 150 = 30.
Subtract the original value from the new value, divide by the original value, then multiply by 100. Going from 100 to 125 is a change of +25%.
Multiply the base value by the percentage, then add that to the base value. Increasing 150 by 20% adds 30, giving 180.
A percentage point is the plain arithmetic difference between two percentages, while percent describes a relative change. Going from 10% to 15% is a rise of 5 percentage points, but a 50% relative increase.