Percentage Change Formula in Excel and Google Sheets
Purpose
Percentage change is the most common calculation I see people struggle to get right in a spreadsheet. The formula itself…
Percentage change is the most common calculation I see people struggle to get right in a spreadsheet. The formula itself is straightforward — subtract the old value from the new value, then divide by the old value — but the mistakes happen in the execution. People subtract in the wrong order and get a sign flip. They forget to divide by the old value, not the new one. They get a #DIV/0! error when the previous period was zero and do not know how to handle it. And they format the result as a number and wonder why they see 0.12 instead of 12%. This post walks through all of it. Percentage change is everywhere in business reporting: revenue growth, cost reduction, headcount change, conversion rate improvement. Once you nail the formula and know how to handle edge cases, you can build proper month-over-month and year-over-year comparison tables in minutes.
Syntax
✓ Excel 2003+
✓ Google Sheets
= Same syntax
=(new_value - old_value) / old_value
This is a constructed formula rather than a built-in function. Format the result cell as Percentage to display with % automatically.
Arguments
| Argument | Required | Description |
|---|---|---|
| new_value | Required | The value at the end of the period you are measuring. This is the current value, the later month, or the target period. |
| old_value | Required | The value at the start of the period. This is the baseline, the previous month, or the comparison period. Must not be zero or the formula returns #DIV/0!. |
How it works
Percentage change measures how much a value changed relative to where it started. The formula is (new minus old) divided by old. If sales went from 10000 to 12000, the change is 2000 and divided by the old value of 10000 gives 0.2 — which formatted as a percentage is 20% growth. If sales went from 10000 to 8000, the change is -2000 and divided by 10000 gives -0.2 which shows as -20% — a decline. The key is always dividing by the starting point, not the ending point. The result is a decimal by default. Format the result cell as Percentage (Ctrl+Shift+%) and Excel or Google Sheets multiplies by 100 and adds the % symbol automatically. For a bare number you can multiply by 100 yourself, but using cell formatting keeps the underlying value as a decimal which plays better with charts and further calculations.
Examples
1
Calculate the month-over-month percentage change in revenue for each product line.
| A | B | C | D | |
|---|---|---|---|---|
| 1 | Product | Mar Revenue | Apr Revenue | Change % |
| 2 | Wireless Mouse | 8200 | 9450 | =(C2-B2)/B2 |
| 3 | USB Keyboard | 5100 | 4800 | -5.9% |
| 4 | Monitor Stand | 3800 | 4200 | 10.5% |
| 5 | Laptop Bag | 2900 | 3100 | 6.9% |
| 6 | HDMI Cable | 1200 | 980 | -18.3% |
| 7 | Webcam HD | 6500 | 7200 | 10.8% |
| 8 | Desk Lamp | 1800 | 1750 | -2.8% |
| 9 | USB Hub | 2100 | 2400 | 14.3% |
| 10 | Mouse Pad XL | 900 | 1050 | 16.7% |
| 11 | Headset Pro | 11000 | 12800 | 16.4% |
Row 2: 15.2%
— Wireless Mouse revenue went from 8200 in March to 9450 in April. (9450-8200)/8200 = 0.152 = 15.2% growth.
Format the result cells as Percentage (Home → Number → Percentage or Ctrl+Shift+%). The formula returns a decimal — formatting handles the display.
2
Calculate year-over-year sales growth, showing N/A as a label when prior year data is zero.
| A | B | C | D | |
|---|---|---|---|---|
| 1 | Region | Year 1 Sales | Year 2 Sales | YoY Growth |
| 2 | North | 125000 | 148000 | =IF(B2=0,"N/A",(C2-B2)/B2) |
| 3 | South | 98000 | 102000 | 4.1% |
| 4 | East | 0 | 25000 | N/A |
| 5 | West | 210000 | 195000 | -7.1% |
| 6 | Central | 87000 | 110000 | 26.4% |
| 7 | North East | 45000 | 52000 | 15.6% |
| 8 | South West | 73000 | 68000 | -6.8% |
| 9 | North West | 0 | 18000 | N/A |
| 10 | South East | 112000 | 128000 | 14.3% |
| 11 | Midlands | 95000 | 99000 | 4.2% |
Row 2: 18.4%
— North grew from 125000 to 148000. (148000-125000)/125000 = 0.184 = 18.4%.
East and North West had no Year 1 sales so the formula returns N/A as a label rather than a #DIV/0! error. The IF check runs before any division so the error never occurs.
Common use cases
1. Show year-over-year revenue growth for a financial summary
=(C2-B2)/B2
2. Calculate the percentage increase in headcount from last quarter to this quarter
=(D2-C2)/C2
3. Track cost reduction percentage for a cost-saving initiative
=(B2-C2)/B2
4. Compare conversion rates between two marketing campaigns
=(D2-C2)/C2
5. Show portfolio growth percentage for an investment tracker
=(C2-B2)/B2
Common errors
#DIV/0!
The old_value (denominator) is zero. You cannot divide by zero and Excel returns this error when the previous period value is zero.
Fix: Wrap the formula in IFERROR: =IFERROR((C2-B2)/B2,""). Or use IF: =IF(B2=0,"",(C2-B2)/B2) to return blank when the base is zero.
Wrong sign — shows positive when it should be negative
The new and old values are in the wrong order. Subtracting new from old instead of old from new flips the sign.
Fix: The formula is always (new minus old) divided by old. Check that C2 is the later period and B2 is the earlier one.
Shows 0.15 instead of 15%
The result cell is formatted as General or Number, so it shows the raw decimal. The formula is correct but the display format needs changing.
Fix: Select the result cells and press Ctrl+Shift+% to apply percentage formatting, or go to Home → Number → Percentage.
Tips and variations
Use IFERROR to handle zero base values cleanly
When previous period values can be zero — new products, first months of trading, or gaps in data — wrap the formula in IFERROR to return a blank or dash instead of #DIV/0!. This keeps your report clean for stakeholders who should not see error codes.
=IFERROR((C2-B2)/B2,"")
Apply conditional formatting to highlight positive and negative changes
Select the percentage change column, apply a Green-White-Red colour scale conditional format, and positive changes appear green while declines appear red without any extra formulas. This gives instant visual interpretation to a table of numbers.
=(C2-B2)/B2
Show the absolute change alongside the percentage
Readers often find raw numbers easier to interpret than percentages. Add a column with =C2-B2 showing the actual increase or decrease in the same units, and a second column with the percentage change. Together they tell a complete story.
=C2-B2
Excel vs Google Sheets
Excel vs Google Sheets
The percentage change formula works identically in Excel and Google Sheets since it uses basic arithmetic operators. Percentage formatting is applied the same way in both applications — select the cell and use the percentage button or format shortcut. No differences to account for when moving formulas between applications.
Related reading
Frequently asked questions
The standard formula is =(new_value - old_value) / old_value. Multiply by 100 if you want a plain number rather than a decimal. Format the cell as Percentage in Excel or Google Sheets to display the result with a % sign automatically.
The formula =(B1-A1)/A1 already returns positive values for increases and negative values for decreases. Format the cell as Percentage and Excel handles the sign automatically. You can also use conditional formatting to colour positive values green and negative values red.
Dividing by zero causes a #DIV/0! error. Wrap the formula in IFERROR: =IFERROR((B1-A1)/A1,"") to return blank when the old value is zero. Alternatively use IF(A1=0,"",( B1-A1)/A1) to handle it explicitly.
No — they are different. Percentage change measures how much a value changed relative to the starting value and has a clear direction (increase or decrease). Percentage difference compares two values without a defined start and end, dividing by the average of the two values. Use percentage change for before/after comparisons. Use percentage difference for comparing two unrelated values.
Write the formula for the first row then copy it down. Use relative references so B2 and A2 shift to B3 and A3 as you copy down. If your data is in a table, the formula adjusts automatically when you press Enter in a table column.