The short version
When a percentage changes, you can describe the change in two ways:
- Percentage points (pp): subtract one percentage from the other. 12% − 10% = 2 points.
- Percent: compare the change with the starting value. 2 ÷ 10 × 100 = 20%.
Both are correct, but they answer different questions.
Examples
| Situation | In points | In percent |
|---|---|---|
| Interest rate rises from 10% to 12% | +2 pp | +20% |
| Inflation falls from 3% to 2% | −1 pp | −33.3% |
| Pass rate goes from 50% to 75% | +25 pp | +50% |
Why it matters
A rate rising “by 2” sounds small, but if it started at 10% the cost of borrowing has gone up by a fifth. The same change can sound bigger or smaller depending on which measure is used.
When someone quotes a change in a rate, ask which one they mean.
Two more percentage traps
Up 25%, then down 25% does not get you back
80 increased by 25% is 100. 100 decreased by 25% is 75, not 80. Each step uses a different starting value.
Two discounts do not add up
20% off and then another 10% off is a total of 28% off, not 30%. The second discount applies to the already reduced price: 100 → 80 → 72.
Want to check a change yourself? The percentage calculator shows both percent change and percentage points.