Summary

The Excel WEEKDAY function returns a number that identifies the day of the week for a given date.

WEEKDAY is useful for weekend checks, work-schedule logic, calendar analysis, staffing plans, recurring reports, and formulas that need to know whether a date falls on Monday, Tuesday, or another weekday.

It is especially helpful when a workbook needs to make decisions based on the day itself rather than the full date. For example, you can use it to flag weekends, count only certain weekdays, trigger different rules for Mondays, or sort dates into a repeating weekly pattern.

Syntax

=WEEKDAY(serial_number, [return_type])

serial_number is the date you want to evaluate. The optional return_type controls how Excel numbers the weekdays.

If you omit return_type, Excel uses its default numbering system. In many real worksheets, adding the second argument makes formulas easier to read later because it makes the weekday logic explicit.

Arguments

• serial_number - A valid Excel date.
• return_type - [optional] A numbering system such as 1, 2, or 3.

In practice, serial_number can come from a typed date, a cell reference, TODAY(), or another formula that returns a date. The key requirement is that Excel must recognize it as a valid date value.

Common Return Types

Microsoft documents several return types, but these are the most commonly used ones.

Return type 2 is often the most practical choice for office-style logic because weekdays become 1 through 5 and weekends become 6 and 7.

That setup makes formulas more readable. For example, WEEKDAY(A1,2)>5 is much easier to understand as a weekend test than trying to handle Saturday and Sunday separately under the default system.

Using WEEKDAY

WEEKDAY is often used inside logical tests. For example, with return type 2, the formula WEEKDAY(A1,2)>5 returns TRUE for Saturday and Sunday. That makes it easy to build weekend flags and work-schedule rules.

Microsoft also recommends using valid Excel dates or DATE(...) rather than ambiguous text dates, because text dates can be interpreted differently depending on regional settings.

If you want a day name like "Wednesday" instead of a number, WEEKDAY is not the only option. You can also use TEXT(A1,"dddd") for display, while keeping WEEKDAY for logic.

A good pattern is to let WEEKDAY handle the calculation layer and let formatting functions handle the display layer. That way your formulas stay numeric and easy to test, while the worksheet can still show friendly labels to users.

Example 1 - Return the Default Weekday Number

The simplest use of WEEKDAY is to convert a date into the default weekday index.

=WEEKDAY(B2)

With the default system, Sunday is 1 and Saturday is 7. This is useful when you are following Excel's built-in numbering style.

For the sample date in this lesson, the result helps you see how Excel maps a normal calendar date into a repeating 1-to-7 cycle. Once you understand that mapping, it becomes much easier to build weekday-based logic elsewhere in the workbook.

Example 2 - Use a Monday-Based Numbering System

Return type 2 is usually easier for business formulas.

=WEEKDAY(B2,2)

With this setup, Monday is 1 and Sunday is 7. That makes weekday ranges easier to understand in work-related logic.

This version is often better for attendance rules, delivery schedules, and staffing formulas because a normal Monday-to-Friday workweek becomes the clean range 1 through 5.

Example 3 - Flag Weekend Dates

You can use WEEKDAY inside a logical test to identify weekends.

=WEEKDAY(B2,2)>5

With return type 2, any result above 5 means Saturday or Sunday. This is a clean pattern for schedule and staffing formulas.

That makes the formula useful as a helper column in larger datasets. Once each row is marked as weekday or weekend, you can filter, count, or highlight records much more easily.

Example 4 - Convert the Result into a Day Label

If you want a short day name, you can wrap WEEKDAY in a function such as CHOOSE.

=CHOOSE(WEEKDAY(B2),"Sun","Mon","Tue","Wed","Thu","Fri","Sat")

This is useful when a report needs a custom text label based on the weekday number.

This approach gives you full control over the displayed labels. For example, you can show short names, full names, abbreviations in another language, or custom business labels that fit the style of your report.

Conclusion Recap

• Summary: WEEKDAY returns a day-of-week number for a date.
• Flexibility: The return_type lets you choose the numbering system.
• Popular choice: Return type 2 is often best for business-week logic.
• Common use: Weekend checks, staffing rules, and weekday-based conditions.
• Display tip: Use TEXT for weekday names and WEEKDAY for logic.
• Best practice: Use real Excel dates for reliable results.