The Basic Formula for Percent Increase

To calculate percent increase in Excel, you need three pieces: the original number, the new number, and a formula that finds the difference between them, then divides by the original. The formula is =(New Value - Original Value) / Original Value. Excel will give you a decimal — multiply by 100 to see it as a percentage, or format the cell as a percentage and Excel does the multiplication for you.

Here is a concrete example. Say cell A1 holds 50 (your original value) and cell B1 holds 75 (your new value). Click on an empty cell — C1 works — and type =(B1-A1)/A1. Press Enter. Excel shows 0.5. Right-click that cell, choose Format Cells, select Percentage, and it displays as 50%. That 0.5 means a 50 percent increase from 50 to 75.

The order matters. If you subtract the new value from the original, you get a negative number, which means a decrease. If you divide by the wrong number, the percentage will be wrong. Always divide by the starting point, not the ending point.

Key Takeaways

  • The percent increase formula is (New Value - Original Value) / Original Value, entered as =(B1-A1)/A1 if your numbers are in cells B1 and A1.
  • Excel shows the result as a decimal by default; format the cell as Percentage to see it as a whole number with a % sign.
  • You can copy the formula down a column to calculate percent increase for many rows at once by selecting the cell and dragging the small square at its bottom-right corner.
  • Negative results mean a decrease, not an increase — a -25% result means the value fell by 25 percent.
  • Use dollar signs in the formula (like $A$1) if you want to compare multiple new values against the same original value without the reference shifting when you copy the formula.

Setting Up Your Data in Columns

Before you write any formula, organize your numbers so Excel can work with them cleanly. Put your original values in one column — say column A — and your new values in the next column, column B. Add labels at the top: "Original" in A1, "New" in B1, and "Percent Increase" in C1. This makes it obvious what each column holds and prevents mistakes.

Start your actual numbers in row 2. If you have ten products with sales figures for January and February, put the January numbers in A2 through A11 and the February numbers in B2 through B11. Leave row 1 for headers. This layout lets you write one formula in C2 and copy it down to C11 without retyping.

Copying the Formula Down Multiple Rows

Once you have entered the formula in one cell, you do not have to type it again for every row. Click the cell with your formula — C2 in the example above. You will see a small square at the bottom-right corner of the cell. Click and drag that square down to C11. Excel copies the formula to every cell you drag across, and it automatically adjusts the cell references so each row calculates its own percent increase.

If dragging feels awkward, there is another way. Click C2, copy it (Ctrl+C on Windows, Command+C on Mac), then select the range C3:C11 and paste (Ctrl+V or Command+V). The result is the same — the formula lands in every cell with the row numbers updated automatically.

Be careful if you want to compare multiple new values against a single original value. If A2 is your baseline and you want to compare B2, B3, and B4 all against A2, use =(B2-$A$2)/$A$2 in C2. The dollar signs lock that reference to A2, so when you copy the formula down, B3 and B4 will still divide by A2, not by A3 or A4.

Formatting as a Percentage

Excel calculates percent increase as a decimal. The number 0.5 means 50 percent, but it does not look like a percentage until you format it. Select the cells holding your results — C2:C11 if you followed the example — and right-click. Choose Format Cells. In the window that opens, click the Number tab (if it is not already selected), then click Percentage in the list on the left.

A dialog box may ask how many decimal places you want. For most purposes, zero decimal places is fine — it shows 50% instead of 50.00%. If you need precision, choose one or two decimal places. Click OK, and Excel converts all selected cells to percentage format. The 0.5 becomes 50%, and 0.125 becomes 12.5%.

Formatting only changes how the number looks, not what it is. A cell showing 50% still holds the decimal 0.5 underneath. If you use that cell in another formula, Excel uses the decimal value, not the displayed percentage.

Handling Negative Numbers and Decreases

When the new value is smaller than the original, the formula produces a negative result. A decrease from 100 to 75 gives you (75-100)/100 = -0.25, or -25%. The negative sign tells you the value went down, not up. This is correct — you are calculating percent change, which includes both increases and decreases.

If you want to show decreases differently — perhaps in red text or with a label — you can use conditional formatting. Select your result cells, go to the Home tab, click Conditional Formatting, and choose a rule. You can make negative numbers appear in red or with a different background color so they stand out from increases.

Some people prefer to calculate percent decrease separately using a different formula, but the same formula works for both. Just read the negative sign as a decrease and the positive sign as an increase.

Common Mistakes to Avoid

The most frequent error is dividing by the wrong number. Remember: you always divide by the original value, the starting point. If you divide by the new value instead, your percentage will be backwards and wrong. Check your formula before copying it down to fifty rows.

Another mistake is forgetting to format the result as a percentage. A decimal like 0.25 looks like a small number, and someone reading the spreadsheet might think the increase was only 0.25 percent instead of 25 percent. Always format your results so the intent is clear.

A third trap is mixing up which column holds which value. If you put new values in column A and original values in column B, your formula will calculate a decrease when there was an increase. Double-check your column labels and make sure your formula references match what you intended.

Using Percent Increase in Larger Spreadsheets

Once you understand the basic formula, you can build it into larger analyses. You might calculate percent increase for sales by month, by product, or by region, then sort the results to see which areas grew fastest. You can also use percent increase in charts — create a column of percent increases and then make a bar chart showing which items grew the most.

If you need to compare percent increase across different time periods or different starting values, keep your original and new values in separate columns so you can recalculate easily. A spreadsheet that tracks monthly sales, for example, might have columns for January, February, March, and so on, with a percent-increase column for each month compared to the previous one.

Frequently Asked Questions

What if my original value is zero?

Excel will show an error, usually #DIV/0!, because you cannot divide by zero. If your original value is zero, percent increase is undefined — there is no meaningful way to express the change. You might note this as "N/A" or "undefined" in that cell instead of using the formula.

Can I calculate percent increase for negative numbers?

Yes, the formula works the same way. If you go from -50 to -25, the formula gives you (-25 - (-50)) / (-50) = 25 / (-50) = -0.5, or -50%. The math is correct, but the interpretation can be confusing because both numbers are negative. Think through what the result means in your context before reporting it.

How do I show percent increase with a plus sign?

Format the cell as a custom number format. Right-click the cell, choose Format Cells, click the Number tab, select Custom, and enter the format code +0.0%;-0.0%. This displays positive results with a plus sign and negative results with a minus sign. Adjust the zeros for more or fewer decimal places as needed.

What is the difference between percent increase and percentage point increase?

Percent increase is what the formula calculates — the change relative to the original value. A percentage point increase is just the difference between two percentages. If something goes from 20% to 25%, that is a 5 percentage point increase, but a 25% percent increase (because 5 divided by 20 is 0.25). Use the formula for percent increase unless you specifically need percentage points.

Can I use this formula for compound growth over multiple periods?

This formula calculates the increase from one point to another. For compound growth — where each period builds on the last — you need a different approach. The compound annual growth rate (CAGR) formula is more complex and involves exponents. If you need CAGR, search for that specific formula, as it is beyond basic percent increase.