YouTip

# PHP juliantojd() Function [ PHP Calendar Reference](#) ## Example Convert a Julian calendar date to a Julian day count, and then convert it back to a Julian calendar date: <?php $jd=juliantojd(6,20,2007); echo $jd . "
"; echo jdtojulian($jd); ?> [Run Example »](#) * * * ## Definition and Usage juliantojd() converts a Julian calendar date to a Julian day count. **Note:** The valid date range for this function is from 4713 BC (Julian calendar) to 9999 AD. The function can calculate back to 4713 BC, but this is not very meaningful. The Julian calendar was established in 46 BC, but some details were not stabilized until 8 AD. Different cultures define the start of the year differently - not all countries agree that January is the first month of the year. Remember that the Gregorian calendar is the currently used worldwide calendar. The [gregoriantojd()](#) function is used to convert these dates to their Julian day counts. **Tip:** See the [jdtojulian()](#) function to convert a Julian day count to a Julian calendar date. ## Syntax juliantojd(_month,day,year);_ | Parameter | Description | | :--- | :--- | | _month_ | Required. A number from 1 to 12, specifying the month. | | _day_ | Required. A number from 1 to 31, specifying the day. | | _year_ | Required. A number from -4713 to 9999, specifying the year. | ## Technical Details | Return Value: | Returns the Julian day number. | | :--- | | PHP Version: | 4+ | * * PHP Calendar Reference](#) [](#)(#) (#)[](#)