How to use the WEEKDAY function

Author: Oscar Cronquist Article last updated on February 07, 2023

The WEEKDAY function converts a date to a weekday number from 1 to 7. You can customize the function so the week starts with any weekday.

A weekday is a day of the week except for Saturday and Sunday, however, the WEEKDAY function returns Saturdays and Sundays as well.

WEEKDAY Function Syntax
WEEKDAY Function Arguments
WEEKDAY Function Video
WEEKDAY Function example
WEEKDAY Function not working
WEEKDAY function - show weekday name
WEEKDAYS between dates
Get Excel *.xlsx file

1. WEEKDAY Function Syntax

WEEKDAY(serial_number,[return_type])

2. WEEKDAY Function Arguments

serial_number	Required. The Excel date value you want to extract the WEEKDAY number from.
return_type	Optional. Determines the type of return value, see table below.

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

3. Video

4. WEEKDAY function example

The WEEKDAY function shown in cell D3 in the image above calculates a number based on a date. The number represents a given weekday based on the provided value in the second argument.

The formula below has no second argument, it defaults to 1 meaning the week begins with a Sunday.

Formula in cell D3:

=WEEKDAY(B3)

5. WEEKDAY function not working

Check your spelling.
Check that you are using a valid Excel date.
Check the number of arguments.

6. WEEKDAY function - show name

WEEKDAY Function show weekday name

Formula in cell C3:

=TEXT(B3, "DDDD")

Step 1 - TEXT function

The TEXT function lets you format values.

TEXT(value, format_text)

value - The string you want to format. You can use a cell reference here or use a text string.

format_text - Formatting code allowing you to change the way, for example, a date or a number is displayed to the Excel user.

Step 2 - Populate arguments

The TEXT function has two arguments.

value - B3

format_text - "dddd"

"dddd" returns the weekday. Lower and upper case letters make no difference.

Check out this article to learn more about formatting codes in the TEXT function.

Step 3 - Evaluate TEXT function

TEXT(B3, "dddd")

becomes

TEXT(43263, "dddd")

and returns "Tuesday".

WEEKDAY Function show weekday name1

Formula in cell C4:

=INDEX({"Sunday";"Monday";"Tuesday";"Wednesday";"Thursday";"Friday";"Saturday"}, WEEKDAY(B4,1))

Explaining formula

Step 1 - Calculate number representing a weekday

WEEKDAY(B4,1)

becomes

WEEKDAY(43184, 1)

and returns 1.

Step 2 - Return weekday name based on position in array

The INDEX function returns a value in a cell range or array based on a row and column number (optional).

INDEX(array, [row_num], [column_num], [area_num])

INDEX({"Sunday";"Monday";"Tuesday";"Wednesday";"Thursday";"Friday";"Saturday"}, WEEKDAY(B4,1))

becomes

INDEX({"Sunday";"Monday";"Tuesday";"Wednesday";"Thursday";"Friday";"Saturday"}, 1)

and returns "Sunday". "Sunday" is the first value in the array.

7. Count days between two given weekdays and two dates

WEEKDAY Function given weekdays between two dates

The image above shows an Excel 365 formula that counts days between two dates and also if they are between two given weekdays.

The start date is specified in cell K3, end date is in cell K4. The start weekday is 3 which represents Tuesday, the table in J11:K18 shows the numbers and corresponding weekday names. The end weekday is 5 which represents Thursday.

The calendar in cell range B4:H9 shows which days (bolded) meet the criteria. Cell K9 displays the result, there are six bolded days in the calendar.

Excel 365 dynamic array formula in cell K6:

=LET(x,SEQUENCE(K4-K3+1,,0),y,WEEKDAY(x+K3,1),COUNT(FILTER(x,(y<=K7)*(y>=K6))))

Explaining formula

COUNT(FILTER(SEQUENCE(K4-K3+1,,0),(WEEKDAY(SEQUENCE(K4-K3+1,,0)+K3,1)<=K7)*(WEEKDAY(SEQUENCE(K4-K3+1,,0)+K3,1)>=K6)))

Step 1 - Calculate the number of days and add one

The minus and plus signs let you perform arithmetic operations in an Excel formula

K4-K3+1

44648 - 44631 +1

equals 18.

Step 2 - Create a sequence of numbers from 0 to 18

The SEQUENCE function creates a list of sequential numbers to a cell range or array. It is located in the Math and trigonometry category and is only available to Excel 365 subscribers.

SEQUENCE(rows, [columns], [start], [step])

SEQUENCE(K4-K3+1,,0)

becomes

SEQUENCE(18,,0)

and returns

{0; 1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17}.

Step 3 - Add date to sequence of numbers

The plus sign lets you perform add numbers in an Excel formula.

SEQUENCE(K4-K3+1,,0)+K3

becomes

{0; 1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17} + 44631

and returns

{44631; 44632; 44633; 44634; 44635; 44636; 44637; 44638; 44639; 44640; 44641; 44642; 44643; 44644; 44645; 44646; 44647; 44648}.

Step 4 - Calculate weekday

WEEKDAY(SEQUENCE(K4-K3+1,,0)+K3,1)

becomes

WEEKDAY({44631; 44632; 44633; 44634; 44635; 44636; 44637; 44638; 44639; 44640; 44641; 44642; 44643; 44644; 44645; 44646; 44647; 44648},1)

and returns

{6; 7; 1; 2; 3; 4; 5; 6; 7; 1; 2; 3; 4; 5; 6; 7; 1; 2}.

Step 5 - Check if number is less than seven

The less than and larger than characters let you check if a value is smaller or larger than a condition, the result is a boolean value TRUE or FALSE. The equal sign and the less than character combined compare if values are equal or smaller than a condition.

WEEKDAY(SEQUENCE(K4-K3+1,,0)+K3,1)<=K7

becomes

{6; 7; 1; 2; 3; 4; 5; 6; 7; 1; 2; 3; 4; 5; 6; 7; 1; 2}<=5

and returns

{FALSE; FALSE; TRUE; TRUE; TRUE; TRUE; TRUE; FALSE; FALSE; TRUE; TRUE; TRUE; TRUE; TRUE; FALSE; FALSE; TRUE; TRUE}.

Step 6 - Check if weekday is larger than one

WEEKDAY(SEQUENCE(K4-K3+1,,0)+K3,1)>=K6

becomes

{6; 7; 1; 2; 3; 4; 5; 6; 7; 1; 2; 3; 4; 5; 6; 7; 1; 2}>=3

and returns

{TRUE; TRUE; FALSE; FALSE; TRUE; TRUE; TRUE; TRUE; TRUE; FALSE; FALSE; TRUE; TRUE; TRUE; TRUE; TRUE; FALSE; FALSE}.

Step 7 - Multiply arrays

The asterisk character lets you multiple values in an Excel formula. Multiplying boolean values always return their numerical equivalents.

TRUE -> 1

FALSE -> 0 (zero)

(WEEKDAY(SEQUENCE(K4-K3+1,,0)+K3,1)<7)*(WEEKDAY(SEQUENCE(K4-K3+1,,0)+K3,1)>1)

becomes

{FALSE; FALSE; TRUE; TRUE; TRUE; TRUE; TRUE; FALSE; FALSE; TRUE; TRUE; TRUE; TRUE; TRUE; FALSE; FALSE; TRUE; TRUE}*{TRUE; TRUE; FALSE; FALSE; TRUE; TRUE; TRUE; TRUE; TRUE; FALSE; FALSE; TRUE; TRUE; TRUE; TRUE; TRUE; FALSE; FALSE}

and returns

{0; 0; 0; 0; 1; 1; 1; 0; 0; 0; 0; 1; 1; 1; 0; 0; 0; 0}.

Step 8 - Filter numbers based on condition

The FILTER function is a new function available to Excel 365 subscribers. It lets you extract values based on a condition or criteria.

FILTER(array, include, [if_empty])

FILTER(SEQUENCE(K4-K3+1,,0),(WEEKDAY(SEQUENCE(K4-K3+1,,0)+K3,1)<7)*(WEEKDAY(SEQUENCE(K4-K3+1,,0)+K3,1)>1))

becomes

FILTER({0; 1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17},{0; 0; 0; 0; 1; 1; 1; 0; 0; 0; 0; 1; 1; 1; 0; 0; 0; 0})

and returns

{4; 5; 6; 11; 12; 13}.

Step 9 - Count numbers in the array

The COUNT function counts all numbers in a cell range or array.

COUNT(value1, [value2], ...)

COUNT(FILTER(SEQUENCE(K4-K3+1,,0),(WEEKDAY(SEQUENCE(K4-K3+1,,0)+K3,1)<7)*(WEEKDAY(SEQUENCE(K4-K3+1,,0)+K3,1)>1)))

becomes

COUNT({4; 5; 6; 11; 12; 13})

and returns 6. There are six numbers in the array.

Step 10 - Shorten formula

The LET function allows you to name intermediate calculation results which can shorten formulas considerably and improve performance.

LET(name1, name_value1, calculation_or_name2, [name_value2, calculation_or_name3...])

LET(x, SEQUENCE(K4-K3+1, , 0), y, WEEKDAY(x+K3, 1), COUNT(FILTER(x, (y<7)*(y>1))))

x - SEQUENCE(K4-K3+1,,0)

y - WEEKDAY(x+K3,1)

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Functions in this article

WEEKDAY

Functions in 'Date and Time' category

The WEEKDAY function function is one of many functions in the 'Date and Time' category.

DATE function

Returns a number that acts as a date in the Excel environment.

DATEDIF function

Returns the number of days, months, or years between two dates. The DATEDIF function exists in order to ensure compatibility with Louts 1-2-3.

DATEVALUE function

Returns an Excel date value (serial number) based on a date stored as text.

DAY function

Extracts the day as a number from an Excel date.

DAYS function

Calculates the number of days between two dates.

EDATE function

Returns a date determined by a start date and a number representing how many months.

EOMONTH function

Returns an Excel date for the last day of a given month using a number and a start date.

HOUR function

Returns an integer representing the hour of an Excel time value.

MINUTE function

Returns a whole number representing the minute based on an Excel time value. The returned number is ranging from 0 to 59.

MONTH function

Extracts the month as a number from an Excel date.

NETWORKDAYS function

Returns the number of working days between two dates, excluding weekends. It also allows you to ignore a list of holiday dates that you can specify.

NETWORKDAYS.INTL function

Calculates the number of working days between two dates, excluding weekends.

NOW function

Returns the current date and time.

SECOND function

Returns an integer representing the second based on an Excel time value

TIME function

Returns a decimal value between 0 (zero) representing 12:00:00 AM and 0.99988426 representing 11:59:59 P.M.

TIMEVALUE function

Returns a decimal number based on a text string.

TODAY function

Returns the Excel date (serial number) of the current date.

WEEKDAY function

Converts a date to a weekday number from 1 to 7.

WEEKNUM function

Calculates a given date's week number based on a return_type parameter that determines which day the week begins.

WORKDAY function

Returns a date based on a start date and a given number of working days (nonweekend and nonholidays).

YEAR function

Converts a date to a number representing the year in the date.

YEARFRAC function

Returns the fraction of the year based on the number of whole days between a start date and an end date.

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You will find functions in this category that calculates random values, round numerical values, create sequential numbers, trigonometry, and more.

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Calculate distributions, binomial distributions, exponential distribution, probabilities, variance, covariance, confidence interval, frequency, geometric mean, standard deviation, average, median, and other statistical metrics.

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Functions that let you manipulate text values, substitute strings, find string in value, extract a substring in a string, convert characters to ANSI code among other functions.

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Get data from the internet, extract data from an XML string and more.

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Excel Tables simplifies your work with data, adding or removing data, filtering, totals, sorting, enhance readability using cell formatting, cell references, formulas, and more.

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Allows you to filter data based on selected value , a given text, or other criteria. It also lets you filter existing data or move filtered values to a new location.

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Lets you control what a user can type into a cell. It allows you to specifiy conditions and show a custom message if entered data is not valid.

Drop Down List

Lets the user work more efficiently by showing a list that the user can select a value from. This lets you control what is shown in the list and is faster than typing into a cell.

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Lets you name one or more cells, this makes it easier to find cells using the Name box, read and understand formulas containing names instead of cell references.

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The Excel Solver is a free add-in that uses objective cells, constraints based on formulas on a worksheet to perform what-if analysis and other decision problems like permutations and combinations.

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An Excel feature that lets you visualize data in a graph.

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Format cells or cell values based a condition or criteria, there a multiple built-in Conditional Formatting tools you can use or use a custom-made conditional formatting formula.

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