Percentages in Excel
There is no percent function in Excel — a percentage is ordinary division, and the % sign is a number format applied on top. Which division you need depends on the question being asked. Percentage of a whole is part divided by whole, so =B2/C2 with the cell formatted as Percentage. Percentage change between two numbers is new minus old, divided by old, so =(C2-B2)/B2. Those are different formulas answering different questions, and swapping them is the commonest percentage error in a spreadsheet. Format matters as much as the formula: =B2/C2 formatted as Percentage reads 25%, =B2/C2*100 left as General reads 25, and doing both at once gives you 2500%.
The formula
=B2/C2 percent OF a whole - part / whole, then format the cell as Percentage
=B2/$C$9 percent of a fixed grand total - lock the total with $ so it survives a fill-down
=(C2-B2)/B2 percent CHANGE from B2 (old) to C2 (new); a negative result is a decrease
=ABS(C2-B2)/AVERAGE(B2:C2) percent DIFFERENCE - neither value is the baseline, so divide by the midpoint
=B2*(1+C2) add a percentage on top, with C2 holding a percent-formatted rate
=B2/(1+C2) strip a percentage back out of a figure that already includes itA worked example
B2 holds last month's revenue of 40,000 and C2 holds this month's 46,000. D9 holds the year-to-date total of 512,000.
=(C2-B2)/B2
The cell stores 0.15 and displays 15% once formatted as Percentage — a 15% increase. =C2/D9 answers a different question entirely: this month as a share of the year, 8.98%. And =(C2-B2)/B2*100 stores 15, which is correct only while the cell stays on General — apply the Percentage format to that same cell and Excel shows 1500%, because the format scales by 100 a second time.
Which one do I need?
Frequently asked questions
Is there a percentage formula in Excel?
There is no PERCENT function. A percentage is division plus a number format: =B2/C2 produces the share, and the % button (or Ctrl+Shift+5) turns 0.25 into 25%. The format changes only what is displayed — the cell still stores 0.25, which is why later formulas that reference it keep working.
Why does my percentage show 2500% instead of 25%?
The value is being scaled twice: the formula multiplies by 100 and the Percentage format multiplies by 100 again. Pick one. Keep =B2/C2 and apply the Percentage format, or keep =B2/C2*100 and leave the cell on General — never both at once.
What is the difference between percentage change and percentage difference?
Percentage change has a direction: one value is the baseline and you divide by it, =(new-old)/old. Percentage difference has no baseline — the two values are peers — so it divides by their average instead, =ABS(a-b)/AVERAGE(a,b). Use change where difference was meant and you get two different answers depending on which number you decided to call "old".
Why does a percentage cell show 0% when the result is not zero?
The Percentage format defaults to zero decimal places, so anything under half a percent rounds to 0% on screen. Home > Increase Decimal reveals the real figure: a stored 0.004 is a genuine 0.4%. Nothing is wrong with the formula, and the underlying value never changed.
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