Percentage Calculator
Three quick percentage tools in one: find a percentage of a number, work out what percent one number is of another, and measure the percentage change between two values.
How to calculate percentages
A percentage is just a fraction out of 100. The word literally means “per hundred”, so 25% is the same as 25 out of 100, or 0.25. Almost every percentage question is one of three types, and this calculator handles all of them.
1. Finding a percentage of a number
result = (percent ÷ 100) × number
Example: a $150 item with 20% off saves you (20 ÷ 100) × 150 = $30.
2. Finding what percent one number is of another
percent = (part ÷ whole) × 100
Example: if you scored 30 out of 150, that's (30 ÷ 150) × 100 = 20%.
3. Finding a percentage change
change = ((new − old) ÷ old) × 100
Example: a price rising from $80 to $100 is a ((100 − 80) ÷ 80) × 100 = 25% increase.
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. For example, 20% of 150 is (20 × 150) ÷ 100 = 30. In the calculator above, use the ‘% of a number’ mode and enter 20 and 150.
How do I work out what percent one number is of another?
Divide the first number by the second, then multiply by 100. For example, 30 out of 150 is (30 ÷ 150) × 100 = 20%. Use the ‘is what % of’ mode for this.
How do I calculate percentage increase or decrease?
Subtract the old value from the new value, divide by the old value, then multiply by 100. If the result is positive it's an increase; if negative it's a decrease. For example, going from 80 to 100 is ((100 − 80) ÷ 80) × 100 = 25% increase.
What's the difference between percentage points and percent?
A percentage change is relative to the starting value, while a percentage point is an absolute difference between two percentages. Going from 10% to 15% is a rise of 5 percentage points, but a 50% increase in relative terms.
CalcOrchard is a free educational tool. Results are calculated live in your browser and rounded for display.