How to Convert Time to Decimal Format Converting time to decimal format just involves basic division. There are 24 hours in a day, 60 minutes in an hour and 60 seconds in a minute.

Microsoft Excel also uses fractional days within dates similar to Julian dates but called serial dates. The time of day is stored as a decimal fraction of the 24 hours clock starting from midnight.

How Do I Change Hours & Minutes Into a Decimal Number in Excel?. In addition to its basic spreadsheet functions, Microsoft Excel also allows writing formulas to perform functions on existing data.