Percentage increase & decrease

How much something went up or down, in percent.

Original value

New value

Increase

15.00%

A difference of 6.00

How it works

Compare an old value with a new one to get the percentage change, or apply a change to a starting value to see where it lands.

Change % = ((New − Old) ÷ |Old|) × 100

Example: A price moving from 40 to 46 is a 15% increase. Going back from 46 to 40 is a 13.04% decrease.

Why isn't a 15% rise cancelled out by a 15% fall?

Because the second percentage is taken from a bigger number. 100 up 15% is 115; 115 down 15% is 97.75, not 100.

What if the old value is zero?

Percentage change is undefined when you start from zero — there is nothing to compare against. Use the absolute difference instead.

Can I use negative numbers?

Yes. The calculator divides by the absolute value of the starting number, so the sign of the change still reads correctly.