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.

For example 0:30:15 – which is zero hours, 30 minutes and 15 seconds – will become 0.0210069444444444, which is a decimal fraction of a day, or 0.02 if you use the default setting of two decimals.