Percentage change calculator
Percentage change measures the difference against where you started: subtract the old value from the new, divide by the old, and multiply by a hundred. The divisor is always the starting point.
- Absolute difference
- 25
- New as a share of old
- 125%
Rates and thresholds
- Formula
- (new − old) ÷ old × 100
- Increase 200 → 250
- +25%
- Decrease 250 → 200
- −20%
How do I calculate percentage change?
Subtract the old value from the new, divide by the old, and multiply by a hundred. A price rising from €200 to €250 changes by (250 − 200) ÷ 200 × 100 = 25%. A negative result means a fall: €250 down to €200 is (200 − 250) ÷ 250 × 100 = −20%.
Why don't a 25% rise and a 25% fall cancel out?
Because the two percentages are taken from different bases. €200 plus 25% is €250; €250 minus 25% is €187.50, not €200. The rise divided by 200, the fall by 250. That is why any claim about a price change is incomplete without saying what the percentage is of.
What is the difference between a percent and a percentage point?
A rate going from 4% to 5% moves one percentage point but 25 percent — because 5 is a quarter more than 4. A percentage point compares two rates absolutely; percentage change compares them relatively. News reports conflate the two, and the gap can be several-fold.
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