Want to know how much a price, salary, score, or website metric has grown? The percentage increase formula shows the change compared with the original value. The key is to divide by the starting value, not the new value.
Quick answer: Percentage increase = ((new value − original value) ÷ original value) × 100.
Percentage increase formula
((New Value - Original Value) / Original Value) x 100
The formula has three steps: subtract the original value from the new value, divide that difference by the original value, and multiply by 100 to express the result as a percentage.
Worked example: a price rises from $80 to $100
- Find the difference: $100 − $80 = $20.
- Divide by the starting price: $20 ÷ $80 = 0.25.
- Convert to a percentage: 0.25 × 100 = 25%.
The price increased by 25%. The new price is 125% of the original price.
How to calculate percentage decrease
The same percentage-change formula works when a value falls. For a decrease from $120 to $90, the difference is $90 − $120 = −$30. Divide −$30 by $120 and multiply by 100: the result is −25%, meaning a 25% decrease.
Another example: salary increase
Suppose a monthly salary changes from $2,400 to $2,640. The increase is $240. Divide $240 by $2,400 to get 0.10, then multiply by 100. The salary increase is 10%.
Common mistakes to avoid
- Dividing by the new number: Percentage change uses the original value as the denominator.
- Confusing dollars with percentages: A $20 increase is an amount; 25% is the relative increase.
- Using zero as the starting value: The formula is undefined when the original value is zero. Explain the absolute change instead.
- Mixing percentage points and percent change: A rate moving from 4% to 5% rises by 1 percentage point, not by 1%.
Calculate the result instantly
Use the Calclio Percentage Calculator to work out a percentage or compare an original value with a new value. For sale prices, try the Discount Calculator.
Frequently asked questions
Can percentage increase be more than 100%?
Yes. If a value rises from 40 to 100, the increase is 150% because the change of 60 is one and a half times the original 40.
Can the answer be negative?
Yes. A negative percentage change means the new value is below the original value, so it represents a decrease.
What if I only know the original value and the percentage increase?
Convert the percentage to a decimal and multiply the original value by 1 plus that decimal. For a 12% increase, multiply by 1.12.
Examples are for learning. Check the original data and rounding rules before using a percentage change in a report or financial decision.