Percentage calculator
Solve the three common percentage questions: percent of a number, one number as a percent of another, and change.
About the percentage calculator
Percentages come up in pay, discounts, grades and budgets, and the three usual questions are easy to mix up. This page has a separate box for each one, so you only fill in the numbers you know. Results update as you type. Nothing leaves your browser.
How it works
- What is X percent of Y: result = Y x X / 100. For example, 15 percent of 80 is 80 x 15 / 100 = 12.
- X is what percent of Y: result = X / Y x 100. For example, 12 is what percent of 80? 12 / 80 x 100 = 15 percent.
- Percentage change from A to B: result = (B minus A) / A x 100. For example, from 50 to 60 is (60 - 50) / 50 x 100 = 20 percent increase.
- A negative result means a decrease. A change from 60 down to 50 is (50 - 60) / 60 x 100, about minus 16.67 percent.
- The old value A cannot be zero in the change formula, because you cannot divide by zero. The calculator shows a message in that case.
How to use it
Step 1
Pick the box that matches your question.
Step 2
Type the two numbers you know.
Step 3
Read the answer, and check the sign to see whether it is an increase or a decrease.
Good to know
- For a quick check on 10 percent of any number, move the decimal point one place to the left.
- When comparing a rise and a fall, remember that the base number is different. Going up 50 percent then down 50 percent does not return you to the start.
- For a salary change, enter the old pay as A and the new pay as B to see the raise percentage.
Questions
What is the difference between percent and percentage points?
If a rate goes from 4 percent to 6 percent, it rose by 2 percentage points, which is a 50 percent increase in the rate itself.
Can the answer be more than 100 percent?
Yes. If a value more than doubles, the change is over 100 percent, and 150 is 150 percent of 100.
How many decimal places does it show?
The result is rounded to two decimal places, which is enough for most everyday uses.