# WorksheetFunction.YearFrac Method (Excel)

Office 2013

Published: July 16, 2012

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.

## Syntax

expression .YearFrac(Arg1, Arg2, Arg3)

expression A variable that represents a WorksheetFunction object.

### Parameters

Name

Required/Optional

Data Type

Description

Arg1

Required

Variant

Start_date - a date that represents the start date.

Arg2

Required

Variant

End_date - a date that represents the end date.

Arg3

Optional

Variant

Basis - the type of day count basis to use.

Double

## Remarks

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.

Basis

Day count basis

0 or omitted

US (NASD) 30/360

1

Actual/actual

2

Actual/360

3

Actual/365

4

European 30/360

• 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.

Note

Visual Basic for Applications (VBA) calculates serial dates differently than Excel. In VBA, serial number 1 is December 31, 1899, rather than January 1, 1900.

• 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.