Excel doesn't have a single dedicated "add percentage" function, but there are a few standard formula patterns depending on what you want to achieve:
1. Add a percentage increase to a number If you want to increase a value by a certain percentage (e.g., add 10% to a price in cell A1):
or referencing a percentage in another cell (say B1 contains 10%):
2. Add a percentage of one number to another If you want to add X% of a number to itself using separate cells:
where A1 is the base number and B1 is the percentage (formatted as a percentage, e.g., 10%).
3. Sum a column of percentages If you simply want to add up percentage values already in cells (e.g., A1:A5), just use the regular SUM function:
Excel will display the result as a percentage if the cells are formatted that way.
4. Calculate percentage increase between two numbers If you want to find out what percentage one number increased relative to another (old value in A1, new value in B1):
Format the result cell as a percentage to see it displayed correctly (e.g., right-click the cell, choose Format Cells, select Percentage).
A key tip: Excel percentages are stored internally as decimals (10% = 0.1), so when typing a percentage directly into a formula, you can either type "10%" or "0.1" — both work the same way. Always check that the cell formatting matches what you expect the result to look like (number vs. percentage format), since this is a common source of confusion.