Percentage Change Calculator
Measure the change from one value to another in percentage terms. The result is positive for an increase and negative for a decrease.
Enter values to calculate.
How to calculate
Percentage change is the signed version of increase and decrease: ((new value โ original value) รท original value) ร 100. A positive result means the value went up, a negative result means it went down โ one formula covers both directions, which is why it's the standard measure in finance and statistics.
To compute it by hand, subtract the original value from the new one first โ keep the sign. Going from 30 to 24, the difference is โ6; divide by 30 to get โ0.2, multiply by 100 for โ20%. Going from 30 to 39 instead, the difference is +9, giving +30%.
Don't confuse percentage change with percentage difference: change always measures against a specific starting value and keeps a direction, while difference treats two values symmetrically using their average, with no 'before' or 'after'. Use change when one number is clearly the baseline; use difference when neither number has priority.
Examples
- From 200 to 250: ((250 โ 200) รท 200) ร 100 = +25%.
- From 200 to 150: ((150 โ 200) รท 200) ร 100 = โ25%.
- From 30 to 24: ((24 โ 30) รท 30) ร 100 = โ20%.
- From 30 to 39: ((39 โ 30) รท 30) ร 100 = +30%.
Frequently asked questions
- What is percentage change?
- Percentage change expresses the difference between an old and new value relative to the old value, keeping the sign to show whether it went up or down.
- Can percentage change be negative?
- Yes. A negative percentage change means the value decreased; a positive value means it increased.
- Is percentage change the same as percentage increase?
- Not quite. Percentage increase is always expressed as a positive number describing growth, while percentage change keeps the sign โ positive for growth, negative for decline. If a value falls, percentage increase doesn't apply at all; you'd switch to percentage decrease. Percentage change works for both cases with one formula.
- Why does percentage change use the original value as the denominator?
- Because the goal is to measure the size of the move relative to where you started. Using the original value keeps the result comparable across different starting points โ a $10 change means more on a $50 base (20%) than on a $500 base (2%), which the formula captures automatically.