where "Minutes" is a decimal number between 0.0 and 1440.0. The portion of the number to the left of the decimal refers to the number of minutes. The decimal portion of the number refers to seconds. 1439.0 minutes is equal to 23 hours and 59 minutes and converts to "23:59:00". There are 1440.0 minutes in 24 hours. Using the formula shown above will return a serial number. To display the serial number in the appropriate format, choose Number from the Format menu (or, on the Format menu, click Cells, and then select the Number tab) and select hh:mm:ss.
To convert hours and minutes from a decimal number to the hh:mm:ss format use the following formula:
Use this formula to convert 4.5 minutes to 0:04:30:
Use this formula to convert 4.5 hours to 04:30:00: