Percentage Change Formula in Excel
Calculate growth rates, month-over-month changes, and YoY comparisons. With proper handling for zero and negative baselines.
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The formula
"Calculate percentage change from old value to new value"
=IFERROR((B2-A2)/ABS(A2),"")Percentage change = (new - old) / |old|. Using ABS handles negative baselines correctly. IFERROR catches division by zero when the old value is 0.
Step-by-step breakdown
- B2 is the new value, A2 is the old value
- (B2-A2) calculates the absolute change
- ABS(A2) uses the absolute value of the baseline to handle negatives
- IFERROR returns blank when A2 is 0 (avoiding #DIV/0!)
- Format the cell as Percentage to display correctly
Edge cases & warnings
- Old value of 0: percentage change is undefined — returns blank
- Old value negative, new value positive: ABS ensures correct positive result
- Both values 0: returns blank (0/0 is undefined)
- Very small old values can produce misleadingly large percentages
Examples
"Old=100, New=125"
25% increase"Old=200, New=150"
-25% decrease"Old=0, New=50"
Blank (undefined)Frequently asked questions
Why use ABS in the denominator?
Without ABS, going from -100 to -50 gives (-50-(-100))/-100 = -50%, which is wrong. Using ABS gives +50%, which correctly shows the value moved toward zero.
How do I calculate YoY growth?
Same formula, just compare the same month across years: =(Jan2026-Jan2025)/ABS(Jan2025). Format as percentage.
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