What is DATEDIF function in Excel?
DATEDIF function is one of Date and Time functions in Microsoft Excel that calculates the fraction of the year represented by the number of whole days between two dates (the start_date and the end_date). For instance, you can use YEARFRAC to identify the proportion of a whole year’s benefits, or obligations to assign to a specific term.
Syntax of DATEDIF function
YEARFRAC(start_date, end_date, [basis])
The YEARFRAC function syntax has the following arguments:
- Start_date Required. A date that represents the start date.
- End_date Required. A date that represents the end date.
- Basis Optional. 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 |
Important:
- Dates should be entered by using the DATE function, or as results of other formulas or functions. For example, use DATE(2018,5,23) for the 23rd day of May, 2018. Problems can occur if dates are entered as text.
- The YEARFRAC function may return an incorrect result when using the US (NASD) 30/360 basis, and the start_date is the last day in February.
DATEDIF formula explanation
- 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, 2018 is serial number 43101 because it is 43,101 days after 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.
Example of DATEDIF function
Steps to follow:
1. Open a new Excel worksheet.
2. Copy data in the following table below and paste it in cell A1
Note: For formulas to show results, select them, press F2 key on your keyboard and then press Enter.
You can adjust the column widths to see all the data, if need be.
| Data | Description | |
| 1/1/2012 | Start date | |
| 7/30/2012 | End date | |
| Formula | Description | Result |
| =YEARFRAC(A2,A3) | Fraction of the year between 1/1/2012 and 7/30/12, omitting the Basis argument. | 0.58055556 |
| =YEARFRAC(A2,A3,1) | Fraction between same dates, using the Actual/Actual basis argument. Because 2012 is a Leap year, it has a 366 day basis. | 0.57650273 |
| =YEARFRAC(A2,A3,3) | Fraction between same dates, using the Actual/365 basis argument. Uses a 365 day basis. | 0.57808219 |