Relative Change Calculator
Calculate the percentage change between two values.
Shows absolute difference, relative percent change, and whether the change is an increase or decrease.
Relative change measures how much a value shifted relative to where it started:
Relative change (%) = (new − old) / |old| × 100
If a stock goes from $80 to $100, the absolute change is $20 but the relative change is +25%. That percentage is more useful when comparing across different scales — a $20 gain on a $100 stock is very different from a $20 gain on a $2,000 stock.
The denominator uses the absolute value of the old value, which handles the case where the starting value is negative. If revenue was −$50 thousand (a loss) and improved to −$10 thousand, the relative change is (−10 − (−50)) / 50 × 100 = 80% improvement.
A few edge cases worth knowing:
If the old value is zero, relative change is undefined (division by zero). Absolute change still works, but percentage change does not.
If the new value is zero, relative change is −100%. That is a complete wipeout.
If both are the same, relative change is 0%.
Relative change vs percentage points: an interest rate rising from 4% to 6% is a 2 percentage point increase but a 50% relative change. Mixing these up is a classic error in news reporting.
This calculator shows the sign — positive for increases, negative for decreases. It always uses the old value as the reference, which is the standard mathematical definition.