Percentages in Excel are simple once you know the formulas and the formatting trick.
Basic percentage formula
To find what percent one number is of another, divide and format as a percent:
=B2/C2
If B2 is 45 and C2 is 60, the result is 0.75. Click the % button on the Home tab to show it as 75%. You do not need to multiply by 100, because the percent format does that for you.
Percent of total
To show each item as a share of the total, lock the total cell with $:
=B2/$B$10
Copy it down and every row is divided by the same total.
Percentage increase or decrease
=(New - Old) / Old
Example: sales went from 80 to 100. =(100-80)/80 gives 0.25, which is 25% growth. A negative result means a decrease.
Add or subtract a percentage
- Add 10% to a price:
=B2*(1+10%) - Subtract 10%:
=B2*(1-10%) - Find 10% of a number:
=B2*10%
Why does it show 0.75 instead of 75%?
The cell is in General format. Select it and apply the Percentage format. If you want fewer or more decimals, use the Increase Decimal and Decrease Decimal buttons, or wrap the formula in ROUND.