How to use the Percentage Change Calculator
- Enter the original value (where you started).
- Enter the new value (where you ended up).
- Read the percentage change. A plus sign means an increase, a minus sign means a decrease.
What does this tool do?
Percentage change compares a new value with an original one. It divides the difference by the original value, which is why going from 80 to 100 is a 25% rise, but going from 100 back to 80 is only a 20% fall.
The calculator also shows the percentage difference, which compares two values against their average. Use it when neither number is the “before” — for example, comparing prices in two shops.
Why use it?
- Avoids the most common mistake: dividing by the new value instead of the original.
- Shows both percentage change and percentage difference, which answer different questions.
- Gives the multiplier (e.g. × 1.25), handy for spreadsheets.
Example: a price rise
A monthly subscription went from $12.99 to $15.99. The difference is $3.00. Divide by the original price: 3.00 ÷ 12.99 = 0.231. Multiply by 100 and the price went up by about 23.1%.
If it later drops back to $12.99, that's a fall of 3.00 ÷ 15.99 = 18.8% — a smaller percentage, because the starting point is now higher.
The formula
Accuracy and limits
- A change from 0 can't be expressed as a percentage (it would be infinite), so the calculator asks for a non-zero original value.
- When the original value is negative, the calculator divides by its absolute value so that a rise is still shown as positive.
Privacy
The calculation happens instantly in your browser. The numbers you enter are not sent to our servers or saved. There's no account to create and nothing to install.
Frequently asked questions
What's the difference between percent and percentage points?
If an interest rate goes from 4% to 5%, it rose by 1 percentage point, but by 25 percent (1 ÷ 4). News reports often mix these up.
Why don't a 50% fall and a 50% rise cancel out?
Because each is measured from a different starting point. $100 falls 50% to $50, and a 50% rise on $50 only takes it back to $75. You would need a 100% rise to get back to $100.
Last reviewed by the M2Toolkit team.