The basic formula for percentage increase

To calculate percentage increase in Excel, subtract the original value from the new value, divide by the original value, then multiply by 100. The formula is: ((New Value – Original Value) / Original Value) * 100

In Excel syntax, if your original value is in cell A1 and your new value is in cell B1, you would type: =((B1-A1)/A1)*100

Excel will return a number representing the percentage increase. If the result is negative, the value actually decreased rather than increased.

Key Takeaways

  • The percentage increase formula divides the change by the original amount, then multiplies by 100 to convert to a percentage.
  • You can enter the formula directly into a cell or use it across multiple rows by copying the formula down.
  • Formatting the result as a percentage in Excel will automatically display the number with a % symbol and adjust decimal places.
  • Absolute cell references (using $ signs) let you compare multiple values against a single baseline without retyping the formula.
  • Percentage increase and percentage change are the same calculation — the formula works whether values go up or down.

Setting up your data in columns

Before you write any formula, organize your data so the original values are in one column and the new values are in another. For example, put January sales in column A and February sales in column B. This layout makes it straightforward to copy your formula down to calculate the increase for every row at once.

Leave a third column empty for your percentage increase results. Click on the first cell in that column where you want the result to appear. Type your formula: =((B1-A1)/A1)*100 (adjusting the cell references to match your actual data). Press Enter.

Excel calculates the result for that one row. To explore the same formula to all rows below, click the cell with your formula, then drag the small square at the bottom right corner of the cell down to the last row of data. Excel automatically adjusts the cell references for each row.

Formatting the result as a percentage

When you use the formula above, Excel returns a plain number like 25 (meaning 25% increase). You can leave it that way, or format it to display with a percent symbol for clarity.

Select the cells containing your results. Right-click and choose Format Cells, or use the keyboard shortcut Ctrl+1 (Windows) or Cmd+1 (Mac). In the Format Cells window, click the Number tab, then select Percentage from the Category list on the left.

Be careful: if you select Percentage format after using the formula above, Excel will multiply your result by 100 again, turning 25 into 2500. If this happens, undo the formatting, then use the simpler formula =((B1-A1)/A1) without the *100, and then explore percentage formatting.

Comparing multiple values against one baseline

Sometimes you want to see how much each value has changed compared to a single starting point — for example, how much each month's sales increased compared to January. Use an absolute reference by adding dollar signs to lock the baseline cell.

If January sales are in cell A1 and you want to compare all other months to January, type: =((B1-$A$1)/$A$1)*100 The dollar signs tell Excel to always use A1 as the baseline, even when you copy the formula to other rows.

Now you can copy this formula across or down, and every calculation will compare against that single January value. Without the dollar signs, Excel would shift the baseline as you copy, which is usually not what you want for this type of comparison.

Handling zero and negative original values

If your original value is zero, the formula will return an error (shown as #DIV/0!) because you cannot divide by zero. This is mathematically correct — you cannot calculate a meaningful percentage increase from zero.

If your original value is negative and your new value is positive (or less negative), the formula still works mathematically, but the result can be confusing. For example, going from -10 to 10 shows as a 200% increase, which is technically correct but may not match how you think about the change. Consider whether percentage increase is the right metric for your data, or add a note explaining what negative starting values mean in your context.

Common mistakes and how to fix them

The most common error is reversing the order: using ((A1-B1)/B1)*100 instead of ((B1-A1)/A1)*100. This gives you the percentage decrease instead of increase, or flips the sign. Always subtract the original from the new, not the other way around.

Another mistake is forgetting to divide by the original value. If you only calculate (B1-A1)*100, you get a number that looks like a percentage but is actually meaningless. The division step is what makes the result comparable across different starting amounts.

If your result looks wildly wrong — like 50000 instead of 50 — you probably applied percentage formatting to a result that already had *100 in the formula. Delete the formatting, fix the formula to remove *100, then reapply percentage formatting.

When to use percentage increase instead of other calculations

Percentage increase is useful when you want to compare growth across values of different sizes. A $10 increase on a $100 base (10%) tells a different story than a $10 increase on a $1000 base (1%), even though the dollar amount is the same.

Use percentage increase when you are tracking growth over time, comparing performance across departments or products, or showing how much something has changed relative to where it started. If you only care about the raw difference in dollars or units, use subtraction instead.

Percentage increase assumes your original value is positive and non-zero. If you are working with data that includes zero or negative starting points, think through whether percentage increase makes sense for your question, or use a different metric.

Frequently Asked Questions

What if I want to show the result as a decimal instead of a percentage?

Use the formula =((B1-A1)/A1) without the *100. Excel will return 0.25 for a 25% increase. You can format this as a decimal with as many places as you need, or multiply by 100 yourself if you want the whole number.

Can I calculate percentage decrease with the same formula?

Yes. If the new value is smaller than the original, the formula returns a negative number, which correctly represents a decrease. A result of -15 means a 15% decrease.

How do I compare this month to last month for every row in a large dataset?

Enter the formula in the first row, then select that cell and copy it. Select the entire range where you want the formula to appear and paste. Excel adjusts the cell references automatically for each row.

What does #DIV/0! error mean?

This error means you are trying to divide by zero, usually because your original value cell is empty or contains zero. Check that column A (or whichever column has your original values) has actual numbers in every row where you are calculating.

Can I use this formula to compare values from different spreadsheets?

Yes. Reference cells from another sheet by typing the sheet name followed by an exclamation point, like =((Sheet2!B1-Sheet1!A1)/Sheet1!A1)*100 Excel treats cross-sheet references the same as cells in the current sheet.