Percentage Increase Calculator

The formula

Example: a price rising from $40 to $52.

((52 − 40) ÷ 40) × 100 = 30% increase

The original value is always the denominator. Dividing by the new value instead is the most frequent error and gives a smaller, wrong answer.

Increases above 100%

A value more than doubling produces an increase above 100%. Going from 20 to 60 is a 200% increase — not 300%, because the increase is the change of 40 relative to 20, not the final value relative to the start.

Put differently: 300% of the original is a 200% increase. "Of" and "increase" are different statements, and headlines frequently conflate them.

Percentages and percentage points

If an interest rate moves from 4% to 6%, that is a rise of 2 percentage points, but a 50% increase in the rate itself.

Both descriptions are correct and they sound wildly different, which is exactly why the distinction gets exploited in arguments about taxes, rates and polling.

Successive increases compound

Two consecutive 10% rises do not total 20%. $100 becomes $110, then $121 — an overall increase of 21%.

This is why multi-year growth figures cannot simply be added, and why an average annual growth rate is not the arithmetic mean of yearly changes.