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 whatever came first: last month’s figure, the starting price, the previous year’s total. The new value is the later one you are comparing it against. A positive answer means the number went up, and a negative answer means it went down. The reason you divide by the old value and not the new one is that percentage change measures growth relative to where you started, so the starting figure is the baseline. Get that part right and everything else is just arithmetic the spreadsheet handles for you.

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 into your result cell and press Enter. To format it as a percent, click the % button in the toolbar, or use Format then Number then Percent. Sheets also has a dedicated function, =TO_PERCENT((B2-A2)/A2), which converts the decimal into a percent display in one step, though the plain formula plus the % button does the same job. If you want the result rounded, wrap it in ROUND, like =ROUND((B2-A2)/A2*100, 1) for one decimal place. Everything transfers between Excel and Sheets here, so a formula built in one opens and works in the other.

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.

Suppose an interest rate goes from 5% to 6%. The change in percentage points is simply 6 − 5 = 1 percentage point. But the percentage change is (6 − 5) ÷ 5 = 20%. Both statements are true and they describe the same move: the rate rose by one percentage point, which is a 20% increase in the rate. News reports mix these up constantly, usually to make a change sound bigger. When you see a percentage of a percentage, check which one is meant. In a spreadsheet, a percentage-point change is just B2−A2, with no division at all.

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 in a cell, for example =(B2-A2)/A2 where A2 holds the old value and B2 the new one. Then format the cell as a percent using the % button, or multiply the formula by 100 to see a plain number. A positive result is an increase and a negative one is a decrease.

Why is my percentage change negative?

A negative result means the new value is lower than the old one, so the quantity decreased. It is correct, not an error. If you only want the size of the change and not its direction, wrap the formula in ABS, as in =ABS((B2-A2)/A2), which always returns a positive figure.

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?

No. Google Sheets and Excel use the identical formula, =(B2-A2)/A2, and both format results as a percent with a toolbar button. Sheets also offers TO_PERCENT to convert a decimal to a percent display in one step. A formula built in one program opens and works in the other.

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?

Wrap the calculation in ROUND, for example =ROUND((B2-A2)/A2*100, 1) for one decimal place, or use the decrease-decimal button in the toolbar. Rounding only changes the display and the stored value if you use ROUND; the decrease-decimal button changes only what you see, not the underlying number.

The Bottom Line

Percentage change is (new − old) ÷ old, and in both Excel and Google Sheets that is =(B2-A2)/A2, formatted as a percent. Divide by the old value, treat a negative sign as a real decrease rather than a mistake, and keep percentage change separate from percentage points when your figures are already percentages. Those few rules cover the vast majority of real spreadsheet work. For a quick one-off answer with no formula at all, run the two numbers through the percentage calculator.