Summary

To calculate the amount represented by a percentage when the total is known, use a formula that multiplies the total by the percentage. In the example shown, the formula in D6, copied down, is:

=C6*total

where total is the named range D15 and column C contains decimal values with the percentage number format applied.

Generic formula

= percentage*total

Explanation 

In this example, the goal is to convert the percentages shown in column C to amounts, where the total of all amounts is given as $1945. In other words, if we know Rent is 36.0%, and the total of all expenses is $1945, we want to calculate that Rent is $700. With "x" as the number we want to find, we have:

=36.0%*1945=x
=0.36*1945
=700.20

Note: in the example, the percentage values in column C are unrounded decimal numbers like 0.359897172, which accounts for the 0.20 difference in the calculation above.

The total of all expenses is in cell D15, which is also the named range "total". To perform this calculation in Excel, we simply multiply the percentage in column C by the total in cell D15. The formula in D6, copied down is:

=C6*total

Named ranges behave like absolute references by default, so the equivalent formula without a named range  is:

=C6*$D$15

For each expense in the table, Excel returns a calculated amount.

Formatting percentages in Excel

In mathematics, a percentage is a number expressed as a fraction of 100. For example, 85% is read as "Eighty-five percent" and is equivalent to 85/100 or 0.85. Accordingly, the values in column C are decimal values.  For example, C6 is approximately 0.36, C7 is approximately 0.18, etc.

To display these numbers as a percentage with the percent sign (%), the Percentage number format has been applied to C6:C13.

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Dave Bruns

Hi - I'm Dave Bruns, and I run Exceljet with my wife, Lisa. Our goal is to help you work faster in Excel. We create short videos, and clear examples of formulas, functions, pivot tables, conditional formatting, and charts.