Percentage Calculator
Percent of, percent change, and increase or decrease by a percent.
Use via API
Percentages: X% of Y, X as a percentage of Y, change from X to Y, increase or decrease X by Y%. Send JSON, get JSON back.
POST https://pithlab.com/api/v1/tools/percentage-calculator
curl https://pithlab.com/api/v1/tools/percentage-calculator \
-H "Authorization: Bearer $PITHLAB_KEY" \
-H "Content-Type: application/json" \
-d '{"mode":"percentOf","a":15,"b":80}'About the Percentage Calculator
Work out percentages instantly: X% of Y, what percent one number is of another, percentage increase or decrease, and adding or subtracting a percentage.
How to use the Percentage Calculator
- Choose the kind of calculation you need.
- Enter the two numbers. Commas and a trailing % sign are fine.
- The answer appears as you type, written out as a full sentence so you can check it reads correctly.
Examples
Input
15, 80
Output
15% of 80 is 12
Input
30, 120
Output
30 is 25% of 120
Input
50, 65
Output
From 50 to 65 is a 30% increase
Input
250, 20
Output
250 increased by 20% is 300
Frequently asked questions
How do I calculate a percentage change?
Subtract the old value from the new value, divide by the old value, and multiply by 100. From 80 to 60 is (60 − 80) ÷ 80 × 100 = −25%, a 25% decrease.
Why isn't a 20% increase undone by a 20% decrease?
Because the second percentage applies to a different base. 100 increased by 20% is 120, and 120 decreased by 20% is 96.
How do I find X% of a number?
Divide X by 100 and multiply by the number. 15% of 80 is 0.15 × 80 = 12.