How to use this calculator
Percentage change compares an ending value with a starting baseline. The order matters. A positive result indicates growth and a negative result indicates decline when the starting value is positive. This is different from percentage difference, which uses the average of two measurements.
Finding a rate from two values
If sales rise from 1,200 to 1,500, the increase is 300. Divide 300 by the starting sales of 1,200: the change is 25%. If the rate is already known, use increase and decrease to calculate the new amount.
Changes greater than 100%
Going from 20 to 50 adds 30. Since 30 is 150% of the starting 20, the increase is 150%; the ending value is 250% of the original. These are two different statements.
Percentage points and relative change
A rate moving from 5% to 6% increases by 1 percentage point. Relative to the starting rate, that is a 20% increase: (6 − 5) ÷ 5 × 100. Enter 5 and 6 in this calculator to find relative change, not percentage points.
Choosing the baseline
The starting value must be positive here. A zero baseline has no defined relative change. An ending value may be negative: 10 to −5 gives −150%, crossing zero. If neither measurement is a starting reference and you want a symmetric comparison, use percentage difference.
The formula
Worked examples
From 80 to 100
(100 − 80) / 80 × 100 = +25%.
From 100 to 80
(80 − 100) / 100 × 100 = −20%.
A rate moves from 5% to 6%
That is 1 percentage point, or a 20% relative increase: (6 − 5) / 5 × 100.
Special cases & input limits
An old value of zero has no defined relative percent change. Negative starting values are rejected because a signed ratio can contradict everyday growth language. A positive starting value and negative ending value are allowed: from 10 to −5 is −150%.
Inputs support a decimal point and scientific notation, up to 30 significant digits and a magnitude of 10⁻²⁰ to 10³⁰, or zero. Select 0–12 display decimal places. Very small or large answers use scientific notation so a nonzero result is not displayed as zero.
A common mistake
Do not use the ending value as the denominator. A rise from 80 to 100 is 25%, although the absolute difference is 20.
Content updated · Calculation methodology