How to Convert Decimal Time Into Seconds in Microsoft Excel

1. Open a new Excel 2010 spreadsheet.
2. Click on cell 'A1,' and type in the time in decimal form. Enter the minutes before the decimal point if you want the result to display like it would on a clock.
3. Click on cell 'A2.' Type the following formula into the cell: '=((A1-INT(A1))*60)' (without quotes). Press 'Enter' to complete the formula, and you will see the number of seconds appear in the box. This formula will remove the minutes from the equation entirely, so if you entered '4.5' into cell A1, your result here would be '30,' as '.5' is exactly half of a minute.
4. Click on cell 'A3.' Type the following formula into the cell: '=(A1/60)/24' (without quotes). Press 'Enter' to complete the formula. This will give you the numerical version of the time, which Excel can then convert into hours, minutes and seconds.
5. Right-click on cell 'A3,' and choose 'Format Cells' from the pop-up menu. Select 'Time' from the list of options on the left side of the window. Choose one of the time options that includes hours, minutes and seconds, but does not include a.m. or p.m.
6. Click 'OK' to close the window. You will see cell A3 change to show you your entered time in hours, minutes and seconds.