Documentation/Calc Functions/HOUR

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    Function name:



    Date and Time


    Determines the hour value from a date expression passed as a date-time serial number or a text string.




    Returns a positive integer in the range 0 to 23, which is the hour value of the given date expression.


    DateTime is the date expression (in quotation marks) or a date-time serial number, or a reference to the cell containing one of those types, from which the hour is to be extracted.

    • If DateTime does not contain a valid date expression, then HOUR reports a #VALUE! error.
    • If DateTime does not contain any time component, then HOUR returns 0 (time 00:00:00).

    Additional details:

    Details specific to HOUR function

    The equation for HOUR is:

    HOUR = INT(DayFraction * 24)


    DayFraction = DateTime – INT(DateTime)

    Take care to understand the function’s behaviour if you ever need to pass date expressions corresponding to negative date-time serial numbers to HOUR (these are dates prior to that selected as the base date on the Tools ▸ Options ▸ LibreOffice Calc ▸ Calculate dialog). For example, if you pass a positive date-time serial number with a fractional part of 0.25 to HOUR, then it will return the value 6 (time 06:00:00). However, if you pass a negative date-time serial number with a fractional part of 0.25 to HOUR, then it will return the value 18 (time 18:00:00).

    Visit Wikipedia’s 24-hour clock page if you need further background information about that topic.

    General information about Calc's Date and Time functions

    Note pin.svg

    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.


    Formula Description Returns
    =HOUR("13:24:59") Here the function returns the value 13. 13
    =HOUR("2021-02-15T16:19:12") Here the function returns the value 16. 16
    =HOUR(44,242.68) The value 44242.68 is the date-time serial number for 2021-02-15T16:19:12. Here the function again returns the value 16. 16
    =HOUR(A1) where cell A1 contains 2020-05-31. Here the function returns 0 because the date expression contains no time component. 0

    Related LibreOffice functions:





    ODF standard:

    Section 6.10.10, part 2

    Related (or similar) Excel functions: