The Basic Percent Change Formula in Excel

To calculate percent change in Excel, use this formula: =(New Value – Old Value) / Old Value. Then format the result as a percentage. If your old value is in cell A1 and your new value is in cell B1, type =((B1-A1)/A1)*100 into an empty cell and press Enter. Excel will show you the percent change as a number.

The multiplication by 100 gives you the percentage directly (for example, 0.25 becomes 25). If you skip the *100 and instead format the cell as a percentage, Excel multiplies by 100 for you automatically — both methods give the same result. Most people find the formatting method cleaner because it keeps the formula shorter.

Percent change tells you how much something grew or shrank relative to where it started. A positive result means growth; a negative result means decline. This works for any paired numbers: sales figures, inventory counts, prices, temperatures, or test scores.

Key Takeaways

  • The percent change formula is (New Value – Old Value) / Old Value, entered as =((B1-A1)/A1) if your values are in columns A and B.
  • Format the result cell as a percentage to display the answer as a percent without multiplying by 100 in the formula.
  • Negative results show a decrease; positive results show an increase.
  • You can copy the formula down a column to calculate percent change for multiple rows at once using relative references.
  • Avoid dividing by zero by using an IF statement to check whether the old value is zero before calculating.

Setting Up Your Data and Cells

Arrange your data so the old value and new value sit in adjacent columns or rows. For example, put the starting value in column A and the ending value in column B. Label your columns clearly — "Starting Sales" and "Ending Sales" — so you know which direction the change runs. This prevents the common mistake of subtracting in the wrong order.

Leave an empty column or cell where you will write the percent change formula. If your data runs down multiple rows (for instance, sales by month), put the formula in column C next to the first pair of values. You will copy it down later.

Writing and Copying the Formula

Click the cell where you want the result to appear. Type =((B1-A1)/A1) and press Enter. Excel calculates the result and shows it as a decimal — for example, 0.25 for a 25 percent increase.

Now format that cell as a percentage. Right-click the cell, select "Format Cells," choose "Percentage" from the Category list, and click OK. The decimal 0.25 becomes 25%. If you have multiple rows of data, click the cell with your formula, then drag the small square at the bottom-right corner of the cell down to copy the formula to the rows below. Excel automatically adjusts the cell references (A1 becomes A2, B1 becomes B2, and so on) so each row calculates its own percent change.

If you prefer to multiply by 100 in the formula instead of formatting, type =((B1-A1)/A1)*100 and press Enter. The result will display as a whole number like 25 instead of a decimal. Either approach works; choose whichever feels more natural to you.

Handling Zero and Negative Starting Values

If your old value is zero, the formula will return a #DIV/0! error because you cannot divide by zero. To prevent this, wrap your formula in an IF statement: =IF(A1=0,"N/A",((B1-A1)/A1)). This tells Excel to display "N/A" if the old value is zero, and to calculate normally otherwise.

Negative starting values create a different problem: the math works, but the result can be misleading. If you started with -10 and ended with 10, the formula shows a 200 percent increase, which is technically correct but often confusing in real-world contexts. In these cases, consider whether percent change is the right metric or whether absolute change (straightforward subtracting the old value from the new value) makes more sense for your analysis.

Real Examples: Sales, Inventory, and Prices

Suppose you sold 100 units last month and 150 this month. Put 100 in A1 and 150 in B1. The formula =((B1-A1)/A1) gives 0.5, which formats to 50%. Your sales grew by half.

If inventory dropped from 500 items to 400, put 500 in A1 and 400 in B1. The formula returns -0.2, or -20%. The negative sign shows the decline. A price that rose from $20 to $24 shows a 20 percent increase. A price that fell from $50 to $40 shows a -20 percent decrease.

These same steps work for any measurement over time: website traffic, test scores, temperature readings, or account balances. The formula structure never changes; only the numbers and labels change.

Comparing Multiple Periods or Categories

If you have data for many months or many products, build a table with old values in one column, new values in the next, and percent change in a third. Label each column clearly. Write the formula once in the first data row, then copy it down to all rows below. Excel handles the cell references automatically, so you end up with percent change calculated for every row without retyping.

You can also use this setup to sort or filter by percent change. For instance, if you have percent change for 20 products, you can sort from highest to lowest to see which products grew fastest or declined most. This makes it straightforward to spot trends and focus on the categories that matter most to your analysis.

Common Mistakes to Avoid

The most frequent error is reversing the order — subtracting the new value from the old value instead of the other way around. This flips the sign of your result. Always subtract the old value from the new value: (New – Old) / Old.

Another mistake is forgetting to format the result as a percentage, then multiplying by 100 in the formula as well. This gives you a result like 2500 instead of 25. Use one method or the other, not both.

Copying a formula without checking that the cell references are correct can also cause problems. If you copy a formula with absolute references (like $A$1) instead of relative references (like A1), every row will calculate against the same old value, which is usually wrong. Use relative references unless you specifically need the formula to always reference the same cell.

Frequently Asked Questions

What if my percent change result shows as a decimal like 0.25 instead of 25%?

Your cell is not formatted as a percentage. Right-click the cell, select "Format Cells," choose "Percentage," and click OK. The decimal will convert to 25%. Alternatively, you can multiply by 100 in the formula: =((B1-A1)/A1)*100.

Can I calculate percent change for negative numbers?

Yes, the formula works mathematically. However, the result can be confusing when the starting value is negative. For example, going from -10 to 10 shows as a 200 percent increase, which is correct but may not match how you think about the change. Consider whether absolute change (the straightforward difference) makes more sense for your situation.

How do I calculate percent change between more than two values?

Calculate percent change for each pair separately. If you have values for January, February, and March, calculate the percent change from January to February in one cell, and from February to March in another. Each calculation uses the same formula with different cell references.

What does a negative percent change mean?

A negative result means the value decreased. For example, -15% means the new value is 15 percent lower than the old value. The formula automatically produces a negative number when the new value is smaller than the old value.

Can I use this formula in Google Sheets or other spreadsheet programs?

Yes. The formula =((B1-A1)/A1) works identically in Google Sheets, LibreOffice Calc, and most other spreadsheet applications. The formatting steps may differ slightly, but the underlying math is the same across all programs.