What is percentage change?

Percentage change is the relative size of the difference between two numbers, expressed as a percent of the original. Formula: ((new − original) / |original|) × 100. A positive result is an increase; a negative result is a decrease.

What if the original value is zero?

Then percentage change is mathematically undefined (you'd divide by zero). The calculator flags this as 'from-zero' so you can communicate the absolute change instead of a misleading percentage. If both original and new are zero, the change is reported as 0%.

How are negative starting values handled?

We use |original| in the denominator so going from -100 to -50 (a +50 improvement) shows as +50%, not -50%. This matches the convention used by financial and economic reporting.

Can percentage change be greater than 100%?

Yes. Going from 50 to 200 is a +300% change. There is no upper bound when the new value grows arbitrarily large.

Percentage Change Calculator

Free percentage change calculator. Enter an original and a new value to get the percent change, signed absolute change, relative change ratio, and the direction (increase / decrease / no change). Correctly handles negative bases by using |original| as the denominator.

Calculate percent change between two values: ((new − original) / |original|) × 100.

Δ% = \frac{V _{n e w} - V _{o l d}}{∣ V _{o l d} ∣} \times 100

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