Percentage Increase Calculator
The formula
Increase (%) = (new value − original value) ÷ original value × 100
The change is always measured relative to the starting value.
Worked examples
- A price goes from €80 to €100: (100 − 80) ÷ 80 = 0.25, an increase of 25%.
- A salary rises from €1,800 to €1,890 a month: 90 ÷ 1,800 = 5%.
- Website visitors go from 1,200 to 3,000: 1,800 ÷ 1,200 = 150% — the audience has been multiplied by 2.5.
If the new value is lower than the original, the result is negative: use the percentage decrease calculator for a positive figure.
Increases don't simply add up
Two successive increases multiply:
| Successive changes | Multiplier | Total change |
|---|---|---|
| +10% then +10% | 1.10 × 1.10 = 1.21 | +21% |
| +5% a year for 5 years | 1.05⁵ = 1.276 | +27.6% |
| +50% then −50% | 1.50 × 0.50 = 0.75 | −25% |
That last line surprises many people: a rise followed by a fall of the same percentage leaves you lower than where you started, because the fall applies to a bigger number.
Percent or percentage points?
When the values are themselves percentages, be precise. If an interest rate goes from 2% to 3%, it has risen by 1 percentage point, which is an increase of 50% in relative terms. News reports often mix the two.
Going the other way
To apply an increase to a value, multiply by (1 + rate): €80 + 25% = 80 × 1.25 = €100. To find the original value before an increase, divide: €100 after a 25% rise was 100 ÷ 1.25 = €80. For average yearly growth over several years, the compound interest logic applies: annual rate = (final ÷ initial)^(1 ÷ years) − 1.
Frequently Asked Questions
How do I calculate a percentage increase?
Subtract the old value from the new one, divide by the old value and multiply by 100. From 80 to 100: 20 ÷ 80 × 100 = 25%.
Can an increase be more than 100%?
Yes. +100% means the value has doubled; +200% means it has tripled. Going from 1,200 to 3,000 is a 150% increase.
Why don't +10% and +10% make +20%?
The second increase applies to the already-increased value: 1.10 × 1.10 = 1.21, so the total increase is 21%.