Percentage Change Calculator
Find the percent increase or decrease between a starting value and an ending value, with the direction and absolute change.
How it works
% change = (new − old) ÷ |old| × 100
The change is measured against the starting value, not the ending one: subtract old from new, divide by the old value, and multiply by 100. A positive result is an increase, a negative one a decrease. Because the base changes, a 25% rise is undone by only a 20% fall.
Worked example
A value goes from 80 to 100. Change = (100 − 80) ÷ 80 × 100 = 25%, so that’s a 25% increase. Going back down from 100 to 80 is (80 − 100) ÷ 100 × 100 = −20%, a 20% decrease.
Frequently asked questions
What’s the difference between percent change and percentage points?
Going from 10% to 15% is a rise of 5 percentage points, but a 50% percent change (5 is half of 10). News about interest rates and polls usually means points; this calculator computes percent change.
Why isn’t a 50% drop fixed by a 50% gain?
Because the base shrinks. 100 falling 50% is 50; 50 rising 50% is only 75. You need a 100% gain to get back — the recovery percent is always bigger than the loss percent.
How do I handle negative starting values?
This calculator divides by the absolute value of the start, so −50 to −25 shows as a 50% increase (it moved up by half the starting size). Some tools report sign differently, so check conventions when comparing.
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This calculator is for educational purposes. Double-check important results before acting on them.