How to Get a Percent of a Total on Microsoft Office Excel 2007

1. Use the SUM function to total the values of the cells you want to include in the total. For example, if you want to determine the total of your income for the year and your income for each month is listed in cells A1 through A12, you would use the function SUM(A1:A12).
2. If you want to take a percentage of the total, enter in a new cell '=SUM(Cells you want to include)*Percentage.' For example, if you wanted to use the income mentioned in step 1 and find 10 percent of that income, you would enter '=SUM(A1:A12)*0.1.'
3. If you want to use a percentage found in another cell, enter that cell instead of a number for percentage in the formula '=SUM(Cells you want to include)*Percentage.' For example, if you had the income tax percentage in cell C5, you would enter '=SUM(A1:A12)*C5'.