How is percentage change calculated?

Percentage change is (new value − original value) divided by the original value, multiplied by 100. A positive result is an increase and a negative result is a decrease.

Why can't I use zero as the original value?

Percentage change divides by the original value, so it is mathematically undefined when the original value is zero — there is no baseline to measure the change against.

Is anything uploaded?

No — the calculation runs entirely in your browser, and the values you enter are never uploaded.

Percentage Change Calculator

Work out the percentage increase or decrease between two values.

Percentage change calculator

Find the percentage increase or decrease between any two numbers. Enter the original value and the new value, and the calculator returns the percentage change together with the absolute difference.

The formula is (new − original) ÷ original × 100. A positive result means an increase, a negative result means a decrease. Everything runs in your browser, so nothing you enter is uploaded.