YEARFRAC

See Also

Calculates the fraction of the year represented by the number of whole days between two dates (the start_date and the end_date). Use the YEARFRAC worksheet function to identify the proportion of a whole year's benefits or obligations to assign to a specific term.

If this function is not available, and returns the #NAME? error, install and load the Analysis ToolPak add-in.

Show How?

On the Tools menu, click Add-Ins.
In the Add-Ins available list, select the Analysis ToolPak box, and then click OK.
If necessary, follow the instructions in the setup program.

Syntax

YEARFRAC(start_date,end_date,basis)

Important Dates should be entered by using the DATE function, or as results of other formulas or functions. For example, use DATE(2008,5,23) for the 23rd day of May, 2008. Problems can occur if dates are entered as text.

Start_date is a date that represents the start date.

End_date is a date that represents the end date.

Basis is the type of day count basis to use.

Basis	Day count basis
0 or omitted	US (NASD) 30/360
1	Actual/actual
2	Actual/360
3	Actual/365
4	European 30/360

Remarks

Microsoft Excel stores dates as sequential serial numbers so they can be used in calculations. By default, January 1, 1900 is serial number 1, and January 1, 2008 is serial number 39448 because it is 39,448 days after January 1, 1900. Microsoft Excel for the Macintosh uses a different date system as its default.
All arguments are truncated to integers.
If start_date or end_date are not valid dates, YEARFRAC returns the #VALUE! error value.
If basis < 0 or if basis > 4, YEARFRAC returns the #NUM! error value.

Example

The example may be easier to understand if you copy it to a blank worksheet.

Show How?

Create a blank workbook or worksheet.
Select the example in the Help topic. Do not select the row or column headers.

Selecting an example from Help
Press CTRL+C.
In the worksheet, select cell A1, and press CTRL+V.
To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Tools menu, point to Formula Auditing, and then click Formula Auditing Mode.

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A	B
Data	Description
1/1/2007	Start date
7/30/2007	End date
2	Actual/360 (see above)
Formula	Description (Result)
=YEARFRAC(A2,A3,A4)	Fraction of the year between the two dates (0.583333333)