Percentage Increase Calculator
Free to use, with no sign up. Your entries stay in this browser; calculations run on your device.
Result
X% of Y = (X / 100) × Y, in the same units as Y. X is what % of Y = (X / Y) × 100%. Change from X to Y = ((Y − X) / |X|) × 100%.
NIST SP 811, section 7.10.2 defines % as 0.01. The U.S. Bureau of Labor Statistics documents the percent-change formula.
Worked example: An original quantity of 80 units rising to 100 units increases by 20 units. Percentage increase = (100 − 80) / 80 × 100 = 25%. A fall from 100 to 80 returns −20%.
Use the same units for the part and whole or the original and new values. Zero denominators are undefined. A negative original value is divided by its size, so a fall always shows as a negative change; the result is not a financial interpretation. Values are limited to ±1 trillion; display rounding does not change the underlying calculation.
How to use this tool
The form starts in percentage-change mode. Enter X as the original value and Y as the new value, in matching units, then Calculate.
Frequently asked questions
How do I calculate percentage increase?
Subtract the original value from the new value, divide by the magnitude of the original value, and multiply by 100.
What does a negative result mean?
The new value is below the original value, so the result is a percentage decrease. For example, 100 to 80 is −20%.
Can the original value be zero?
No. A relative change from zero requires division by zero and is undefined. Enter a nonzero original value.