Percentage Calculator

How the Percentage calculator works

Formula. Percent of a number is (number × percent) / 100. A percent increase is original + (original × percent / 100). A percent decrease subtracts that same amount. Percent difference is ((value 2 − value 1) / value 1) × 100.

Example. 25% of 80 is (80 × 25) / 100 = 20. Increasing 80 by 25% is 80 + 20 = 100. Decreasing 80 by 25% is 80 − 20 = 60. The percent difference from 80 to 100 is ((100 − 80) / 80) × 100 = 25%.

Limitation. Percent difference divides by the first value, so the result changes if the two values are swapped, and it is undefined when the first value is 0.