# Documentation/Calc Functions/YEARFRAC

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YEARFRAC

Date and Time

## Summary:

Calculates the number of years (including any fractional part of a year) between two dates.

## Syntax:

YEARFRAC(StartDate; EndDate[; Basis])

## Returns:

Returns a non-negative real number which is the number of years between the two dates passed as arguments, assuming a specified (or default) day count convention.

## Arguments:

StartDate is the date (in quotation marks) or a date-time serial number, or a reference to the cell containing one of those types, which is the start or end date of the period for which the calculation is to be carried out.

EndDate is the date (in quotation marks) or a date-time serial number, or a reference to the cell containing one of those types, which is the end or start date of the period for which the calculation is to be carried out.

Basis is a positive integer from 0 to 4 or a reference to a cell containing that integer which is chosen from a list of options and indicates how the year is to be calculated. For more information, visit Wikipedia's Day count convention page.

Basis Calculation
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.
• If either StartDate or EndDate is not a valid date expression, then YEARFRAC reports a #VALUE! error.
• YEARFRAC ignores any time components of StartDate and EndDate.
• If Basis is non-numeric, then YEARFRAC reports an invalid argument error (Err:502).
• If Basis is a non-integer value, then YEARFRAC truncates it to an integer.
• If (after any truncation) Basis does not equal 0, 1, 2, 3, or 4, then YEARFRAC reports an invalid argument error (Err:502).

## Additional details:

### General information about Calc's Date and Time functions For convenience the information in this subsection is repeated on all pages that describe functions in the Date and Time category.

• Internal to Calc, a date/time value is handled as a real number and this is sometimes referred to by the term date-time serial number. For example, 2021-02-08 12:00:00 corresponds to the date-time serial number 44235.5. The integer part of a date-time serial number (before the decimal point) is the number of days since a defined start date. The fractional part of a date-time serial number (after the decimal point) is the time of day expressed as a fraction of a day. For example, 0.25 is equivalent to 06:00:00 and 0.75 is equivalent to 18:00:00.
• Calc uses 1899-12-30 as the default start date (day 0) but you can go to Tools > Options > LibreOffice Calc > Calculate to select alternative start dates; however, unless you have specific requirements for compatibility with legacy spreadsheet applications, we recommend that you do not change this setting. If you copy and paste cells containing date values between different spreadsheets, check that both documents are set to use the same start date to avoid unexpected changes to the dates displayed.
• Negative date-time serial numbers correspond to dates earlier than Calc's start date. Calc calculates all dates back to 15th October 1582 using the Gregorian calendar. The day before this is 4th October 1582, and Calc uses the Julian calendar for earlier dates.
• A date-time serial number is the same as any other number, except that we usually choose to display it formatted as a date/time. You can enter a number in a cell and then change the cell’s formatting to display the value as a date/time. You can also enter a date/time in a cell and then change the cell’s formatting to display the date-time serial number.
• For clarity, the descriptions of the Calc functions within these wiki pages use the standard ISO 8601 format for date and time because this should be independent of your selected locale settings. The default date format on your computer may be different. When entering dates as part of formulas, slashes or dashes used as date separators may be interpreted as arithmetic operators. Therefore, dates entered in this format are not recognized as dates and result in erroneous calculations. To keep dates from being interpreted as parts of formulas either use the DATE function or place the date in quotation marks and use the ISO 8601 notation. Avoid using locale dependent date formats which may produce errors if the document is loaded under different locale settings.
• Time zone information is not used by Calc’s Date & Time functions.
• If you only wish to enter two digits of the year (for example 21 instead of 2021), Calc needs to know whether you mean 2021 or 1921. Go to Tools > Options > LibreOffice > General to view or adjust the range of years which Calc will use to interpret two-digit year values.
• Calc contains logic to decide how to treat text when encountered as an operand in an arithmetic operation or as an argument to a function that expects a number instead. In this context, unambiguous conversion is possible for ISO 8601 dates and times in their extended formats with separators. For example, the simple formula `=1 + "2021-02-08"` will usually give the result `2021-02-09` (when formatted as a date). However, this logic may be affected by the settings on the Detailed Calculation Settings dialog, accessed by selecting Tools > Options > LibreOffice Calc > Formula and pressing the Details button in the Detailed Calculation Settings area. If a #VALUE! error occurs, it may be because the Generate #VALUE! error option is selected, in which case you should experiment with one of the other self-explanatory options in the Conversion from text to number drop-down.

## Examples:

Formula Description Returns
=YEARFRAC("2020-01-01"; "2020-07-01") Here the function returns 0.5. The Basis argument is omitted and so YEARFRAC applies the default value of 0. There is half of one year between the two dates specified. 0.5
=YEARFRAC("2020-07-01"; "2020-01-01"; 0) Here the function again returns 0.5. Note that swapping the two date arguments had no impact on the result. 0.5
=YEARFRAC(F1; F2; F3) where cell F1 contains the date `2021-01-01`, cell F2 contains the date `2021-04-01`, and cell F3 contains the value `4`. Here the function returns 0.25. The Basis value of 4 corresponds the so-called European method, in which the year is assumed to comprise 12 months of 30 days each. 0.25
=YEARFRAC(44197; 44287; 3) Here the function returns 0.246575342. 44197 and 44287 are the date-time serial numbers for 2021-01-01 and 2021-04-01 respectively. Basis value 3 uses the exact number of days in each month, with a total of 365 days in the year. (Note that the number of days in the first three months of the year 2021 is 31+28+31 (90) which, when divided by 365, gives the value returned). 0.246575342

YEARFRAC