How to Calculate Percentage Increase or Decrease in Excel

Calculating percentage change in Excel is one of those skills that looks intimidating until you see the formula — then it clicks instantly. Whether you're tracking sales growth, comparing monthly expenses, or analyzing survey results, Excel handles percentage increase and decrease calculations cleanly once you know the structure.

The Core Formula for Percentage Change

The universal formula for percentage change is:

((New Value – Old Value) / Old Value) × 100

In Excel, you don't need to multiply by 100 manually if you format the cell as a percentage. The working formula in a cell looks like this:

=(B2-A2)/A2 

Where A2 is the original value and B2 is the new value. Format that cell as a percentage (Home → Number → Percentage), and Excel displays the result as a proper percentage — positive for an increase, negative for a decrease.

Step-by-Step: Setting Up the Calculation 📊

1. Enter Your Data

Place your original (old) values in one column and your new values in the next. For example:

2. Write the Formula in Column C

Click cell C2 and type:

=(B2-A2)/A2 

Press Enter. You'll see a decimal like 0.3 or -0.25.

3. Format as Percentage

With C2 selected, go to Home → Number group → click the % button (or press Ctrl + Shift + %). Excel converts the decimal to a readable percentage — 30% or -25%.

4. Copy the Formula Down

Click C2, then drag the fill handle (the small square at the bottom-right of the cell) down to apply the formula to additional rows.

Handling Common Errors

When the Original Value Is Zero

If your Old Value is 0, Excel returns a #DIV/0! error — you can't divide by zero, mathematically or otherwise. Wrap the formula in an IFERROR function to handle this gracefully:

=IFERROR((B2-A2)/A2, "N/A") 

This displays "N/A" instead of an error, keeping your spreadsheet clean.

Negative Original Values

When the starting value is negative, the formula still runs but the result may be counterintuitive. A value moving from -100 to -50 looks like a 50% decrease mathematically, but in context (like a loss shrinking) it's an improvement. The formula doesn't know intent — you'll need to interpret results carefully when negative numbers are involved.

Absolute vs. Relative Percentage Change

Some users confuse percentage change (relative) with percentage point change (absolute). If a rate goes from 20% to 25%, the percentage point change is 5 points — but the percentage increase is 25%:

=(0.25-0.20)/0.20 = 25% increase 

This distinction matters a lot in financial reporting, survey analysis, and academic contexts.

Calculating Percentage Increase and Decrease Separately

If you want to show only increases or only decreases, use IF logic:

Show only increases:

=IF(B2>A2,(B2-A2)/A2,"—") 

Show only decreases:

=IF(B2<A2,(B2-A2)/A2,"—") 

Show the magnitude of decrease as a positive number:

=IF(B2<A2,(A2-B2)/A2,"—") 

This is useful for dashboards where you want losses displayed as positive red numbers rather than negative values.

Using the ABS Function for Magnitude Only

If you only care about how much something changed — not whether it went up or down — wrap the numerator in ABS():

=ABS(B2-A2)/A2 

This always returns a positive percentage, useful when you're measuring volatility or variance regardless of direction.

Applying Percentage Change Across Larger Datasets 🔢

For larger datasets, named ranges and structured table references make formulas easier to read and maintain. If your data is formatted as an Excel Table (Insert → Table), references become descriptive:

=[@New]-[@Original])/[@Original] 

This is especially helpful when collaborating — formulas stay readable even to users unfamiliar with the original spreadsheet layout.

For time-series analysis, you might calculate month-over-month change by comparing each row to the one above it:

=(B3-B2)/B2 

Copied down a column of monthly figures, this gives you a rolling percentage change for each period.

Variables That Affect Which Approach Works Best

Several factors determine which version of this formula suits your situation:

• Data structure — single comparison vs. running series vs. multi-column comparison
• Presence of zeros or negatives — requires error handling or formula modification
• Audience — a dashboard for executives needs clean formatting and suppressed errors; an analyst's working sheet might not
• Excel version — older versions lack some dynamic array features, though the core percentage formulas work universally
• Output use — whether you're feeding the result into a chart, another formula, or presenting it directly affects how you format and structure the output

A straightforward two-column before/after comparison works cleanly for most basic use cases. But once your data involves edge cases — zeros, negatives, large rolling datasets, or conditional logic — the formula you need starts to depend on specifics that only your spreadsheet layout can determine.