The Excel Yearfrac function returns the fraction of a year that is represented by the number of whole days between two supplied dates.
The syntax of the function is:
Where the arguments are as follows:
|start_date||-||The start of the period (this date is included in the calculation).|
|end_date||-||The end of the period (this date is included in the calculation).|
|The financial day count basis rules are explained in detail on the Wikipedia Day Count Convention page|
Note that Microsoft advises that you do not type dates directly into functions, as Excel may interpret text representations of dates differently, depending on the date interpretation settings on your computer. Therefore the start_date and end_date arguments for the Yearfrac function should be input as either:
The spreadsheet below shows five examples of the Excel Yearfrac function. In each case, the function is used to calculate the year fraction between 1st January 2015 and 31st March 2015. However, each case uses a different Day Count Basis.
See the Microsoft Office website for further examples of the Excel Yearfrac function.
If you get an error from the Excel Yearfrac function, this is likely to be one of the following:
|#NUM!||-||Occurs if the value of the supplied [basis] argument is less than 0 or greater than 4.|