1. Open a Microsoft Excel spreadsheet.
2. Input a number in one cell, which corresponds to an amount. Input another number in another cell corresponding to the total.
3. Select a blank cell where to calculate the percentage between the two. The percentage formula is equal to the amount divided by the total. The total is usually greater than the amount.
4. Type '=Cell1/Cell2' without the quotation marks in the blank cell, where cell1 corresponds to the location of the first cell and cell2 corresponds to the location of the second cell. Press 'Enter' to get the fractional value. For example, if you placed an amount in cell A1 and the total in cell A2 and you selected cell A3 to calculate the percentage, then A3 should contain the formula: =A1/A2
5. Select the cell you want to format as a percentage to convert the fraction into a percentage. To format a row, click on the row number on the leftmost side of the worksheet to select the entire row. To format a column, click the column letter on the upper side of the worksheet to select the entire column. To format the entire worksheet, select the rectangular box on the upper left side corner between the first row (Row 1) and the first column (column A.) To format nonadjacent cells, click the first cell then press the 'CTRL' key. Continue holding the 'CTRL' key while clicking on other cells you want to format as percentage.
6. Right-click anywhere on the cell you want to format and click 'Format Cells...' to open the Format toolbox.
7. Go to the 'Number' tab and under 'Category' choose 'Percentage.'
8. Choose the decimal places on the 'Decimal places' drop down. The default is set to 2, which means that the percentage will have up to two decimal places like 0.25%.
9. Click 'OK' to close.