Everyday math · 4 min read

Percentage change explained with examples

Percentage change compares a new value with an original value. It is useful for prices, measurements, performance, and budgets, as long as the original value is the reference point.

The percentage-change formula

Subtract the original value from the new value, divide that difference by the original value, and multiply by 100: ((new - original) / original) × 100. A positive result is an increase; a negative result is a decrease.

A quick example

If a monthly bill rises from $80 to $92, the change is $12. Divide $12 by $80 and multiply by 100: the bill increased by 15%. The denominator is $80 because it is the starting value.

Percentage points are different

When comparing rates, percentage points describe the direct difference between two percentages. A rate moving from 20% to 25% rises by 5 percentage points, but its relative percentage increase is 25%.

Use the calculator, then check the reference

Try the percentage calculator with the original and new values. For refunds, discounts, and other consequential decisions, confirm whether the provider defines the comparison against the original amount, the final amount, or a stated baseline.

This guide explains the arithmetic, not a financial, medical, tax, or legal decision. Keep the original inputs with any result you share.