The result is the number of the years (including fractional part) between StartDate and EndDate.
YEARFRAC(StartDate; EndDate; Basis)
StartDate and EndDate are two date values.
Basis (optional) is chosen from a list of options and indicates how the year is to be calculated.
|0 or missing||US method (NASD), 12 months of 30 days each|
|1||Exact number of days in months, exact number of days in year|
|2||Exact number of days in month, year has 360 days|
|3||Exact number of days in month, year has 365 days|
|4||European method, 12 months of 30 days each|
What fraction of the year 2008 lies between 2008-01-01 and 2008-07-01?
=YEARFRAC("2008-01-01"; "2008-07-01";0) returns 0.50.