Percentage Increase Calculator
This free percentage increase calculator shows how much a value has gone up or down between two numbers, as a percentage. Type the original value and the new value and you get the percentage change, the absolute difference and the formula used, so you can check the result or reuse it in a spreadsheet.
How to use the percentage increase calculator
- Enter the original (starting) value, for example last year’s price.
- Enter the new value, for example this year’s price.
- Press Calculate. A positive result in green is an increase; a negative result in red is a decrease.
The percentage increase formula
Percentage change = (new value − original value) ÷ original value × 100
The difference is always divided by the original value, because the question is “how much did it change compared with where it started?”. That is why the calculator cannot work when the original value is zero: there is nothing to compare against.
Worked examples
- A product that cost $80 and now costs $100 rose by (100 − 80) ÷ 80 × 100 = 25%.
- If the price falls back from $100 to $80 the change is (80 − 100) ÷ 100 × 100 = −20%. The same $20 is a smaller share of the higher starting price, which is why a 25% rise is undone by a 20% fall, not a 25% fall.
- A salary that goes from 1,500,000 to 1,830,000 increased by 22%.
Percentage change vs. percentage points
When the values are already percentages, be careful with the wording. If an interest rate moves from 4% to 5%, it rose by 1 percentage point, but by 25 percent in relative terms. News and reports often mix the two, and this calculator gives you the relative change.
How to reverse a percentage increase
If you know the final value and the percentage, divide instead of subtracting. A price of $120 after a 20% increase came from 120 ÷ 1.20 = $100, not from 120 − 20%. The same idea works for discounts: a price of $75 after a 25% discount was originally 75 ÷ 0.75 = $100.
Where people use percentage change
- Comparing prices, rents or bills between two dates and tracking inflation in your own spending.
- Measuring business growth: sales, visitors, followers or revenue month over month.
- Checking a pay rise or comparing job offers.
- Following investments, weight, training results or any number that changes over time.
Frequently asked questions about percentage increase
What is the formula for percentage increase?
((New value − Original value) ÷ Original value) × 100. A positive result is an increase and a negative result is a decrease.
Does this calculator also work for decreases?
Yes. If the new value is lower, the result is shown as a negative percentage.
Can the percentage increase be more than 100%?
Yes. Going from 50 to 150 is a 200% increase, because the value tripled.
Why can’t the original value be zero?
The formula divides by the original value, and dividing by zero is undefined.
How many decimals does the result show?
Two decimals, which is precise enough for prices, salaries and statistics. Round further if you need to.
Quick reference: percentage change examples
| Original | New | Change | Percentage change |
|---|---|---|---|
| 50 | 60 | +10 | +20% |
| 80 | 100 | +20 | +25% |
| 100 | 80 | −20 | −20% |
| 200 | 300 | +100 | +50% |
| 40 | 10 | −30 | −75% |
| 25 | 100 | +75 | +300% |
Common mistakes to avoid
- Dividing by the new value. Always divide by the original value; otherwise a rise from 80 to 100 looks like 20% instead of 25%.
- Adding up percentages over several periods. Two yearly increases of 10% give 21% in total, not 20%, because the second increase applies to an already larger number.
- Mixing percentage points and percent. Going from 10% to 12% is 2 percentage points, or a 20% relative increase.
- Ignoring the sign. A negative result means a decrease, even if the numbers are large.
Related tools
- Compound Interest Calculator – see how a yearly percentage grows over many years.
- Salary After Tax Calculator – check what a pay rise means after tax.
- Guide: how to calculate percentage increase by hand
- All free tools
Further reading: Relative change on Wikipedia.