How to Calculate Percentage Change in Excel and Google Sheets

The Percentage Change Formula

Percentage change is the difference between two values, divided by the original value, then multiplied by 100.

The old value is the starting figure. With a positive starting value, a positive result means an increase and a negative result means a decrease. Zero has no defined percentage change, and a negative starting value requires explanation because the sign can be counterintuitive.

How to Do It in Excel

Say your old value sits in cell A2 and your new value in B2. Here is the whole process.

1. Click an empty cell where you want the answer, for example C2.
2. Type =(B2-A2)/A2 and press Enter. This gives you the change as a decimal, so 0.3 rather than 30.
3. With that cell selected, click the percent button (the % sign) in the Number group on the Home tab. Excel now shows 30% instead of 0.3.
4. To copy the formula down a column, grab the small square at the bottom-right corner of the cell and drag, or double-click it.

Formatting the cell as a percent is the neat way to do it, because the underlying value stays a true fraction that other formulas can use. If you would rather see a plain number like 30, multiply the formula by 100 instead: =(B2-A2)/A2*100, and leave the cell formatted as a normal number. Pick one approach and stay consistent, or you will end up comparing a 30 against a 0.3 somewhere and wondering why a chart looks wrong.

How to Do It in Google Sheets

Google Sheets uses the exact same formula, which is handy if you move between the two.

Type =(B2-A2)/A2 and format the result as Percent. To show one decimal place, adjust the cell’s displayed decimal places; the stored value remains available at its original precision. Google Sheets also provides TO_PERCENT, but that function is not a reason to assume every Sheets formula is portable to Excel. For a plain number such as 30.0 instead of 30.0%, use =ROUND((B2-A2)/A2*100,1) with Number format, not Percent format.

Worked Examples

Two examples, one going up and one going down, cover almost everything you will meet.

An increase. Sales rose from 50 units last month to 65 this month. The change is (65 − 50) ÷ 50 = 15 ÷ 50 = 0.30, which is a 30% increase. In a spreadsheet with 50 in A2 and 65 in B2, the formula =(B2-A2)/A2 returns 0.30, and the % button turns it into 30%.

A decrease. A price dropped from 80 to 60. The change is (60 − 80) ÷ 80 = −20 ÷ 80 = −0.25, a 25% decrease. The minus sign is the spreadsheet telling you the number fell, and it is correct, not an error to strip out. If you only care about the size of the move and not the direction, wrap the formula in ABS: =ABS((B2-A2)/A2) returns 0.25 either way.

Notice that a rise from 50 to 65 is 30%, but a fall from 65 back to 50 is not 30%: it is (50 − 65) ÷ 65 = −23.1%. The percentages differ because the baseline changed. That asymmetry trips up a lot of people reading year-on-year figures.

Percentage Change vs Percentage Points

This distinction matters most when the numbers you are comparing are themselves percentages, and getting it wrong can make a headline sound far more dramatic than it is.

If an interest rate rises from 5% to 6%, the difference is one percentage point, while the relative increase is (6 − 5) ÷ 5 = 20%. If A2 and B2 contain actual spreadsheet percentages, such as 5% and 6%, use =(B2-A2)*100 with Number format to display 1 percentage point. The raw difference =B2-A2 is 0.01, which displays as 1% with Percent format. Label the result clearly.

Common Mistakes

• Dividing by the new value instead of the old one. The denominator is always the starting figure. This is the mistake that produces answers in the right ballpark but subtly wrong, so it often goes unnoticed.
• Forgetting to format the cell, then reading 0.3 as “0.3%” instead of 30%. Either format as percent or multiply by 100, not neither and not both.
• Doing both: multiplying by 100 and formatting as a percent, which shows 3000%.
• Trying to calculate percentage change from a starting value of zero. Dividing by zero has no answer, and the spreadsheet shows a #DIV/0! error. Growth from nothing has no percentage; state it as an absolute number instead.
• Confusing a percentage-point change with a percentage change when both figures are already percentages.

Frequently Asked Questions

What is the formula for percentage change in Excel?

Use =(new-old)/old, for example =(B2-A2)/A2, then format the result as Percent. Alternatively multiply by 100 and use Number format. For a positive starting value, the sign shows increase or decrease; zero or negative baselines require special care.

Why is my percentage change negative?

With a positive starting value, a negative result means the value decreased. A negative baseline can reverse that interpretation, so explain such cases separately. ABS gives a nonnegative magnitude, including zero, but removes direction and does not resolve a misleading baseline.

Do I divide by the old value or the new value?

Always divide by the old value, the one you started from. Percentage change measures how much something grew or shrank relative to its starting point, so the starting figure is the baseline. Dividing by the new value is the most common mistake and gives a wrong answer that often looks plausible.

Is the formula different in Google Sheets?

Both support =(B2-A2)/A2 with percentage formatting. Google Sheets also has TO_PERCENT; use the shared arithmetic formula when you need the calculation to work in both applications.

How do I calculate percentage change from zero?

You cannot express it as a percentage. Dividing by an old value of zero has no mathematical answer, and a spreadsheet returns a #DIV/0! error. When something grows from nothing, report the change as an absolute number instead, such as “up by 40 units,” rather than a percentage.

What is the difference between percentage change and percentage points?

Percentage points are the plain arithmetic difference between two percentages, so 5% to 6% is one percentage point. Percentage change divides that difference by the original, so 5% to 6% is a 20% change. Both are correct; they answer different questions, and reports often blur them to make a move sound larger.

How do I stop the result showing too many decimals?

With =(B2-A2)/A2 formatted as Percent, adjust the displayed decimal places to show, for example, 30.0%. This changes the display only. ROUND changes the calculated value. If you multiply by 100 inside ROUND, leave the result in Number format to avoid displaying 3000%.

The Bottom Line

For a positive, nonzero starting value, percentage change is (new − old) ÷ old, formatted as a percent. Check the baseline and keep percentage change separate from percentage-point change. Negative starting values need additional context: for example, going from −100 to −50 is a numerical increase but the usual formula returns −50%. Report the absolute change and explain the baseline when a percentage would mislead. See Microsoft’s percentage guidance and Google’s TO_PERCENT documentation.