The Problem
In this guide, we will explore exactly how to calculate percent change in Excel. Looking at old and new numbers side by side is not enough when you need to understand how much something actually grew or dropped.
A change of 500 means one thing on a small number and something very different on a large one. That is why percent change matters. It shows the movement relative to the starting value, not just the raw difference.
In this challenge, you will compare Q1 revenue with Q2 revenue for each item, calculate the growth rate, and then finish a short summary that shows the total starting revenue and how many products grew by more than 20 percent.
How We Solve It
The standard formula is (New - Old) / Old. First find the difference, then divide that difference by the original value.
That gives you a decimal result which Excel can display as a percentage. Positive values mean growth, and negative values mean decline.
Method 1: Standard Percent Change
Method 1: Use the standard percent change formula based on old and new values.
This is the clearest version of the formula because it shows each step directly. You subtract the old value from the new one, then divide by the old value.
It is a good default when you want the logic to be easy to explain to someone else reading the sheet.
=(C2-B2)/B2
Method 2: Compact Ratio Version
Method 2: Use a compact ratio formula that returns the same percent change.
You can also write percent change as New / Old - 1. It leads to the same result, just in a shorter form.
Some people prefer this version because it is fast to type and avoids extra parentheses.
=C2/B2-1
Method 3: Measure Change Size Only
Method 3: Use ABS when you want the size of the change without caring about direction.
If the goal is to measure how large the movement was, not whether it went up or down, you can wrap the difference in ABS.
That changes all results to positive magnitudes, which is useful in some comparison or variance dashboards.
=ABS(C2-B2)/B2
Function Explanation
1. Division
Division is what turns a raw difference into a relative change. Without it, you only know the amount of change, not how large that change is compared with the starting point.
That is why percent change is more useful than raw subtraction in many reports.
2. Parentheses
Parentheses make the order of operations clear. In the standard formula, they ensure that the difference is calculated before the division happens.
That keeps the logic easy to read and avoids accidental formula mistakes.
3. Percent Format
Excel stores these results as decimals, so formatting matters. A result like 0.25 is easier to read as 25%.
That is why percentage formatting is part of the workflow, even though the underlying formula stays the same.
If the old value is 0, percent change formulas can break because you would be dividing by zero. That is a useful edge case to watch in real reports.
Calculate the percent change from Q1 to Q2 for each product, then review the summary section to see the total starting revenue and how many items grew by more than 20 percent. This gives you both the row-level trend and a quick performance snapshot in one sheet.