webutilkit

Percentage Calculator

Calculate a percentage of a number, what percent one number is of another, or percent change.

50

The three questions this answers

“X% of Y” answers, for example, what 25% of 200 is. “X is what % of Y” flips that around: given a part and a whole, it finds the percentage the part represents. “% change from X to Y” measures growth or shrinkage between two values, as a percentage of the starting value.

Percent change vs. percentage points

Going from 50 to 60 is a 20% increase, since the change (10) is 20% of the starting value (50). This is easy to confuse with a change from 50% to 60%, which is usually described as a 10 percentage point increase — the same absolute gap, described a different way.

Common uses

Working out a discount or tip, checking how much a value grew year over year, or figuring out what share of a total a specific number represents.

Frequently asked questions

What is the difference between percent change and percentage points?

Percent change is relative to the starting value — going from 50 to 60 is a 20% increase. A change from 50% to 60% is instead often described as "10 percentage points," a different and larger-sounding way to state the same absolute gap.

Why is percent change undefined starting from zero?

Percent change is relative to the starting value, and dividing by zero has no defined result — any increase from zero is technically an infinite percentage increase.