📈 Percentage Change Calculator
Percentage change = (new − old) ÷ old × 100 — going from 80 to 100 is a 25% increase. Enter your values below — results update instantly, entirely on your device.
(100 − 80) ÷ 80 × 100
How the percentage change calculator works
change % = (new value − original value) ÷ |original value| × 100. Positive results are increases, negative are decreases.
Example: From 80 to 100 → (100 − 80) ÷ 80 × 100 = 25% increase.
Mind the asymmetry: a 25% increase from 80 reaches 100, but getting back from 100 to 80 is only a 20% decrease. Percentage changes are always relative to the starting value, which is why a 50% loss needs a 100% gain to recover.
Frequently asked questions
What is the percentage change formula?
(new − old) ÷ old × 100. Example: 250 → 300 is (300 − 250) ÷ 250 × 100 = 20% increase.
What is the difference between percentage change and percentage points?
If interest rises from 4% to 6%, that is a 2 percentage-point rise but a 50% relative increase. Points subtract the raw percentages; percentage change is relative to the start.
Why do a 50% drop and a 50% gain not cancel out?
Because each change applies to a different base: 100 → 50 (−50%) → 75 (+50% of 50). After a 50% loss you need a 100% gain to break even.
Is this percentage change calculator accurate and private?
Yes. It uses the standard published formula, shows its working under every result, and computes locally in your browser — your inputs are never sent to a server, and the page works offline.