The Time or Date that signifies the start of a time period. Usually accompanied by Base, the length (months) or end of the time period.
This is probably the most common variable in the library. It either signifies a one-off time, or the start of a timeperiod. By "Time", we mean "Date", since Business Functions does not deal with times within a day.

The Time is input and stored as a Date Number, which is usually the number of days from 1st Jan 1900. We say "usually" because there is a date system, which originated on the Macintosh, which used the number of days from 1st Jan 1904, and you can (optionally) still use this in Excel for Windows, although we really don"t recommend it.

You need to enter Time as date number eg 36550. You can"t directly enter into the function a date as text ("1 Jan 2005") or in date format (1/1/2005). However, by far the best way of entering a time or date into a function is to first of all input the date into a cell by itself, in which case Excel will adjust anything you throw at at eg 1/1/2005. Then reference that cell in the cell that contains the function.

Time is often accompanied by Base, in which case the two together define a Timeperiod, where Time is the start of the timeperiod, and Base is either the length of the timeperiod, in exact months, or the end of the timeperiod, as a date.

BF stored its times as the very beginning of the day in question, so 38353.00 is very first instant of the day 1/1/2005 - it is the zero-th second after midnight, the very start of the day.

How Base adds itself to Time
Time and Base often appear together in a function to define a time period. If Base is defined in months, the question is: how is the exact number of months added to Time?
  • When Base adds itself to Time to define a timeperiod, it retains the day wherever possible. So 15th Jan plus 3 months comes to 15th April.
  • When Time is the last day in the month, the date of the end of the timeperiod will always come to the end of a month, irrespective of the days in the month. Therefore 29th Feb plus 6 months comes to 31st Aug, but 28th Feb plus 6 months comes to 28th Aug.
  • By locking onto specific days in the month, Time and Base are not adhering to a particular daycount convention, instead they are are just operating add you would intuitively expect.
Example: 1/1/2003
Variable Values
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