Percentage Change
Free Percentage Change: use =(New-Old)/Old and format the result as a percentage.
Increase of 48 units
How it works
In Excel or Google Sheets, use =(New-Old)/Old and format the result as a percentage.
Put the original value and the new value in two cells.
In a third cell type =(New-Old)/Old, clicking the two cells.
Press Enter and format the cell as a percentage.
Drag the formula down a column to compute the change for many rows at once.
What this does
Percentage change tells you how much a value rose or fell relative to where it started, which is what makes a €20 move on €100 (20%) and a €20 move on €400 (5%) comparable. Subtracting old from new gives the absolute change; dividing by the old value rebases it to a rate. A positive result is an increase, a negative one a decrease.
A worked example
A price goes from 120 to 168: =(168-120)/120 = 0.4, formatted as 40% — a 40% increase. If it instead fell to 90, =(90-120)/120 = −25%. The tool above colours increases green and decreases red and also shows the raw unit change, so you see both the rate and the absolute move. Percentage change is the language of every trend: month-on-month revenue, year-on-year growth, price moves, conversion shifts. It turns two raw numbers into a comparable story anyone can read at a glance.
Common mistakes
- Dividing by the new value instead of the old — the base must be the starting point.
- Leaving the result as a decimal (0.4) instead of formatting it as 40%.
- Averaging percentage changes across periods instead of compounding them.
- Dividing by zero when the original value is 0, which has no defined percentage change.
FAQ
Increase vs difference — same thing?
Percentage increase/decrease keeps the sign and uses the old value as base. Percentage difference between two independent figures usually divides by their average instead.
How do I show it with a + or − sign?
Apply a custom number format like +0.0%;−0.0% so increases and decreases are visually signed without extra formulas.
Why is my percentage huge?
Almost always a missing percent format (a value of 0.4 shown as 40 instead of 40%) or dividing by a very small base value.
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