About the Percentage Calculator
Work out percentages quickly: what is 15% of 200, what percent 30 is of 120, the percentage increase from 80 to 100, and more. Each calculator shows the formula it used, so you can check the working for homework, discounts, tips, grades and business reports.
How to use the Percentage Calculator
- Find the calculator that matches your question.
- Type your numbers into the boxes.
- Read the answer and the formula underneath.
Features
- What is X% of Y
- X is what percent of Y
- Percentage increase or decrease from X to Y
- X is Y% of what number
- Increase or decrease a number by a percentage
- Formula shown for every answer
Percentage formulas
X% of Y = (X / 100) x Y. X as a percent of Y = (X / Y) x 100. Percentage change from A to B = ((B - A) / |A|) x 100. A positive result is an increase and a negative result is a decrease.
Frequently asked questions
How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply by the number. For example, 15% of 200 = 0.15 x 200 = 30.
How do I calculate percentage increase?
Subtract the old value from the new value, divide by the old value and multiply by 100. From 80 to 100: (100 - 80) / 80 x 100 = 25%.
How do I work out a discount?
Use "Decrease a number by a percentage". For 20% off $50, the sale price is $50 x (1 - 0.20) = $40.
Why can't I calculate change from zero?
Percentage change divides by the starting value, and dividing by zero is undefined, so a change from 0 cannot be expressed as a percentage.