Percentage Formula in Google Sheets
The core idea is part ÷ whole, then format the cell as a percentage. Here are the common cases.
=A2/B2
Part divided by whole. Then format the cell as Percent (Format â–¸ Number â–¸ Percent) so 0.25 shows as 25%.
How it works
A percentage is a ratio: divide the part by the whole and Sheets stores it as a decimal (0.25). Applying Percent formatting multiplies the display by 100 and adds the % sign — the underlying value stays 0.25, so further maths still works.
Variations
Percentage change (new vs old)
=(B2-A2)/A2
Positive = increase, negative = decrease. Format as percent.
Percent of a grand total
=B2/SUM(B$2:B$100)
$ locks the total range so it stays fixed when you drag down.
Add a percentage
=A2*(1+20%)
Adds 20% to A2.
What number is X% of Y
=20%*A2
20% of A2.
Examples
| Scenario | Formula |
|---|---|
| Score as a percentage | =Correct/Total |
| Month-over-month growth | =(ThisMonth-LastMonth)/LastMonth |
FAQ
Why does my percentage show as 2500% instead of 25%?
The value is already a percentage but you divided again, or you applied Percent formatting to a value that was already 25. Divide part by whole once, then format.
How do I show a percentage with no decimals?
Select the cells and click the decrease-decimals button, or Format â–¸ Number â–¸ Custom number format â–¸ 0%.