Tool to find the day of the week of a given date. Each date corresponds to a day of the week on a given calendar. There is an algorithm to calculate the day of the week of a date.

Day of the Week of a Date - dCode

Tag(s) : Date and Time, Fun/Miscellaneous

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Calculation needs any date (day, month, year) to search in the Gregorian Calendar (or Julian before 1582) and to know some mathematics formula.

There are algorithms that allow a mental calculation (not necessarily easy), but they become false for dates before 1900. Basically, the principle is to make a calculation from the numbers day, month, year, and deduce a modulo 7 value, with 0 for Monday, 1 for Tuesday, 2 for Wednesday, 3 for Thursday, 4 for Friday, 5 for Saturday and 6 for Sunday.

__Example:__ The first january 2000 was a Saturday.

Overall, it is highly probable that before 1900 the days of the week were not perfectly managed in all regions. The Gregorian calendar was not as widespread in Europe, and globally, the values proposed by dCode before 1900 are mathematically correct, but may have shifts with the practices of the time that were not rigorous...

There are two differences, the first difference is about the calculus of leap years and the second one, which is a consequence, the Gregorian Calendar had a jump of several days in 1582.

In France, the day after December 9, 1582, was December 20, 1582.

In Europe, the day after Thursday 4 October was Friday 15 October 1582 (this version is used on dCode).

When there may be confusion or uncertainty about the calendar used, historians specify the location and name of the calendar used.

__Example:__ January 1st of the Gregorian Calendar

dCode retains ownership of the online 'Day of the Week of a Date' tool source code. Except explicit open source licence (indicated CC / Creative Commons / free), any 'Day of the Week of a Date' algorithm, applet or snippet (converter, solver, encryption / decryption, encoding / decoding, ciphering / deciphering, translator), or any 'Day of the Week of a Date' function (calculate, convert, solve, decrypt / encrypt, decipher / cipher, decode / encode, translate) written in any informatic language (Python, Java, PHP, C#, Javascript, Matlab, etc.) and no data download, script, copy-paste, or API access for 'Day of the Week of a Date' will be for free, same for offline use on PC, tablet, iPhone or Android ! dCode is free and online.

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day,week,weekday,find,search,date,birthdate,year,calendar,monday,tuesday,wednesday,thursday,friday,saturday,sunday

Source : https://www.dcode.fr/day-week-date

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