# WEEKDAY

## Rational

Converts a serial number of a day in the week

## Description

The Excel WEEKDAY function returns an integer between 1 and 7 the corresponds specific day of a week. Example; to find dayth (07-04-2018: Cell-B6) number of a week starting from Monday, use =WEEKDAY(B6,2) that returns ‘6’.

## Syntax

=WEEKDAY(serial_number,[return_type])

## Parameters

serial_number – A valid argument of date, string representation or a serial number of a specific date.
return_type [optional] – Setting custom start day of a week.

## Return Value

Return value is an integer between 1 and 7.

## Key Notes

• In simple term, WEEKDAY function helps you figure out which day of the week a date falls on.
• Use VLOOKUP function to return days alphabetically.
• The WEEKDAY function throws an integer even if the referring cell in the formula is blank.
• Problems can occur if dates are entered as text or manually in the parenthesis as an argument.
• It is preferred to change the format as general for the resulting cell.

Following table shows Return_type [optional] arguments for the WEEKDAY function:

 Return_type Number returned 1 or omitted Numbers 1 (Sunday) through 7 (Saturday). 2 Numbers 1 (Monday) through 7 (Sunday). 3 Numbers 0 (Monday) through 6 (Sunday). 11 Numbers 1 (Monday) through 7 (Sunday). 12 Numbers 1 (Tuesday) through 7 (Monday). 13 Numbers 1 (Wednesday) through 7 (Tuesday). 14 Numbers 1 (Thursday) through 7 (Wednesday). 15 Numbers 1 (Friday) through 7 (Thursday). 16 Numbers 1 (Saturday) through 7 (Friday). 17 Numbers 1 (Sunday) through 7 (Saturday).

### WEEKNUM

The WEEKNUM function finds the week number of date and week start day, i.e., week starting from Monday (05-06-2018-C7), use =WEEKNUM(B7,2) that returns ‘23’.

### ISOWEEKNUM

The ISOWEEKNUM function return ISO week number considering a week begins on Monday. Example; date (09-03-2017), use = ISOWEEKNUM(date) that returns 10.

### DAYS

The DAYS function returns the difference between two dates. To find days duration between two dates, use DAYS(“01/08/2018″,”01/05/2017”) that returns ‘457’.