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.

How do I tell an increase from a decrease?

A positive result means the value went up (an increase) and a negative result means it went down (a decrease). The tool also shows the absolute change with a + or − sign.

What is the difference between percentage change and percentage points?

Percentage change measures the relative change from the original value. Percentage points measure the simple difference between two percentages — going from 10% to 15% is a 5 percentage-point rise but a 50% increase.

How does it handle a negative original value?

The tool divides by the absolute value of the original, so the sign of the result reflects the direction of the change rather than the sign of the starting number.

Can the percentage change be more than 100%?

Yes. If the new value is more than double the original, the increase exceeds 100% — for example, going from 50 to 150 is a 200% increase.

Is anything uploaded?

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

Percentage Change Calculator

Percentage change calculator

Find the percentage increase or decrease between any two numbers — prices, scores, populations, traffic, anything that moves over time. Enter the original value and the new value, and the calculator returns the percentage change along with the absolute difference, so you can see both the relative and the actual change at once.

How it works

The calculator uses the standard percentage-change formula, dividing by the absolute value of the original so the sign reflects direction:

percentage change = (new − original) ÷ |original| × 100
absolute change   = new − original

A positive result is an increase, a negative result is a decrease. The result is undefined when the original value is zero, because there is no baseline to compare against.

Example

Original 80, new 100:

Absolute change: 100 − 80 = +20
Percentage change: 20 ÷ 80 × 100 = +25% (an increase)

Reverse it — from 100 down to 80 — and the change is −20 ÷ 100 × 100 = −20%.

Original	New	Change
80	100	+25%
100	80	−20%
50	150	+200%

Everything runs in your browser, so nothing you enter is uploaded.