Percentage Formula in Excel

Q: How do I calculate percentage change in Excel?

Use =(new-old)/old and format the cell as a percentage. Or use =(new-old)/old*100 to get the number without formatting.

Excel handles percentages using the same arithmetic as a standard calculator. The key is understanding whether your values are already stored as decimals (0.20) or as whole numbers (20), since this affects how you write the formula.

1. Find X% of a number

If cell A1 contains the number and B1 contains the percentage as a whole number (e.g. 20 for 20%):

=A1*B1/100

If B1 is already formatted as a percentage (stored as 0.20):

=A1*B1

Example: A1 = 250, B1 = 20 (meaning 20%). Formula =A1*B1/100 returns 50.

2. What percent is X of Y?

Divide the part by the whole and format the result cell as a percentage:

=A1/B1

Then format the cell as percentage (Home → Number → %). Excel multiplies by 100 and adds the % symbol automatically.

Or use the explicit formula to get the number without formatting:

=A1/B1*100

Example: A1 = 45, B1 = 180. Formula returns 0.25 (formatted as percentage: 25%).

3. Percentage change (increase or decrease)

=(B1-A1)/A1

Format the result cell as a percentage, or:

=(B1-A1)/A1*100

Example: A1 = 80 (old), B1 = 100 (new). Result = (100−80)/80 = 0.25 → formatted as 25%.

4. Add a percentage to a number

=A1*(1+B1/100)

Example: Add 20% to $150 in A1 with B1 = 20. Result = 150 × 1.20 = 180.

5. Remove a percentage from a number

=A1*(1-B1/100)

Example: Remove 15% from $200. Result = 200 × 0.85 = 170.

6. Apply a percentage column to a range

To apply 20% VAT to a column of prices (prices in A2:A100, result in B2:B100):

=A2*1.20

Type this in B2, then drag the fill handle down. Or use an absolute reference for the rate so you can change it in one cell:

=A2*(1+$D$1/100)

Put the rate (e.g. 20) in D1. Changing D1 updates all calculations instantly.

Formatting tips

Format as percentage: Select cells → Ctrl+Shift+% (or Home → Number → %). Excel multiplies the stored value by 100 for display.
Watch out: If you type 20% in a cell, Excel stores 0.20. If you type 20, Excel stores 20. The formulas above assume you type the number (20), not the percentage (20%).
Decimal places: Right-click → Format Cells → Percentage → set decimal places as needed.

Quick reference

Task	Formula (values as numbers)
X% of Y	`=Y*X/100`
X as % of Y	`=X/Y*100`
% change from A to B	`=(B-A)/A*100`
Add X% to Y	`=Y*(1+X/100)`
Remove X% from Y	`=Y*(1-X/100)`

For quick calculations without opening a spreadsheet, use the free Percentage Calculator on this site.

FAQ

How do I calculate a percentage in Excel without a formula?

Type the number, press *, type the percentage followed by %, then press Enter. For example: =150*20% returns 30.

Why does my percentage formula show a decimal instead of a percentage?

The cell is formatted as a number, not a percentage. Select the cell and press Ctrl+Shift+% to apply percentage formatting.

How do I calculate percentage change in Excel?

Use =(new-old)/old and format the cell as a percentage. Or use =(new-old)/old*100 to get the number without formatting.

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