An Excel percentage formula can calculate what portion one value represents, apply a discount or increase, or measure change between two amounts.
The key is choosing the right relationship between the cells—and formatting the result as a percentage without multiplying it twice.
How do you calculate a percentage of a total in Excel?
To find what percentage a part is of a whole, divide the part by the total.
If the part is in cell B2 and the total is in C2, enter:
=B2/C2Format the result cell as Percentage.
For example, if B2 contains 25 and C2 contains 200, the formula returns 12.5% when displayed as a percentage.
In Excel, select the result cell and choose Home > Number > Percent Style, or press Ctrl+Shift+% in Windows.
You can adjust decimal places with the Increase Decimal or Decrease Decimal buttons.
The formula itself returns a decimal value: 0.125 is displayed as 12.5% when percentage formatting is applied.
Calculate a percentage directly
If you want a fixed percentage of a value, multiply by the percentage.
For 15% of the amount in A2, use:
=A2*15%If A2 is 80, the result is 12.
You can also store the rate in a cell, such as B2 containing 15%, and use =A2*B2.
Referencing a rate cell makes the formula easier to update and reuse.
How do you add a percentage increase?
To increase an amount by a percentage, multiply the original amount by one plus the rate.
If A2 contains 200 and B2 contains 10%, enter:
=A2*(1+B2)The result is 220.
The 1 represents the original 100% of the amount; adding 10% produces 110% of the original.
You can enter the rate directly as =A2*(1+10%), but a separate rate cell is more convenient when you need to change the increase.
How do you subtract a percentage or apply a discount?
To reduce an amount by a percentage, multiply it by one minus the rate.
For an amount in A2 and a discount rate in B2, use:
=A2*(1-B2)With an original price of 80 and a discount of 15%, the result is 68.
The formula returns the discounted price.
To calculate the discount amount alone, use =A2*B2, which returns 12 in this example.
Keep the two results distinct in a worksheet: one cell can show the discount amount, and another can show the price after discount.
This helps prevent accidentally subtracting a discount twice.
How do you calculate percentage change?
Percentage change compares a new value with an original value.
Subtract the original from the new value, then divide by the original.
If the original is in A2 and the new value is in B2, enter:
=(B2-A2)/A2Format the result as a percentage.
If the original value is 80 and the new value is 100, the result is 25%, indicating an increase.
If the new value is 60, the result is -25%, indicating a decrease.
A negative percentage is not an error: it means the new value is below the original.
To show only the magnitude of the change, you could use =ABS((B2-A2)/A2), but this removes the direction, so use it only when direction does not matter.
How do you find a value after applying a percentage?
Sometimes the final amount and rate are known, and you need to recover the original.
If a value after a 20% increase is in B2, divide it by 1 plus the increase rate:
=B2/(1+20%)If the final value is 120, the original was 100.
For a value after a 20% reduction, divide by the portion that remains:
=B2/(1-20%)For a final value of 80 after a 20% discount, this returns 100.
Do not simply add or subtract 20% of the final value: the percentage is based on the original amount.
Percentage formula examples at a glance
- Part as a percentage of total:
=B2/C2; format as Percentage. - Percentage of an amount:
=A2*15%. - Increase by a rate in B2:
=A2*(1+B2). - Discount by a rate in B2:
=A2*(1-B2). - Percentage change from A2 to B2:
=(B2-A2)/A2. - Original amount before an increase:
=B2/(1+rate).
Why is my Excel percentage formula showing the wrong result?
Check how the rate is entered and how the result is formatted.
If a cell contains 15%, Excel stores it as 0.15.
Multiplying by that cell is correct.
If you type 15 to represent 15%, a formula such as =A2*15 multiplies the amount by fifteen, not by fifteen percent.
Enter 15% or use =A2*15%.
Also avoid multiplying by 100 when the result cell is already formatted as Percentage.
For example, =B2/C2*100 returns 12.5 for a 25-of-200 comparison.
Applying percentage formatting then displays 1250%.
Use =B2/C2 with percentage formatting, or keep the multiplied result as a regular number if you specifically need the value 12.5.
Prevent division by zero
A percentage-of-total formula cannot divide by a zero total.
If C2 may be zero or blank, handle that case explicitly:
=IF(C2=0,0,B2/C2)This returns 0 when the denominator is zero.
If you prefer a blank result for an unavailable comparison, use =IF(C2=0,"",B2/C2).
The formula still needs Percentage formatting for nonblank results.
Do percentage formulas work in Google Sheets?
These basic formulas and percentage-formatting principles work in current desktop versions of Excel, Excel for the web, and Google Sheets.
Use the same cell references and operators in each.
Keyboard shortcuts can vary by platform, so use the formatting controls in the ribbon or toolbar if a shortcut does not work.
For formulas filled down a column, relative references such as A2 adjust automatically.
If the percentage rate is fixed in B1, lock that reference with dollar signs so it stays in place when you copy the formula: =A2*(1+$B$1).
In Excel, pressing F4 while editing a reference cycles through reference styles.
Google Sheets also supports dollar signs for fixed references.