Formula Guide

The Excel WEEKDAY Function
explained simply

WEEKDAY returns which day of the week a date falls on, as a number — useful for flagging weekends or scheduling logic.

ExcelPro · 4 min read · Updated June 2026
Contents
  1. What does WEEKDAY do?
  2. Syntax
  3. 4 examples
  4. Common mistakes
  5. FAQ

What does WEEKDAY do?

WEEKDAY takes a date and returns a number representing which day of the week it is — by default, 1 for Sunday through 7 for Saturday.

A second, optional argument lets you change which day counts as 1, which matters if your week starts on Monday rather than Sunday.

Syntax

=WEEKDAY(date, [return_type])
ArgumentDescription
date requiredThe date to check.
return_type optionalControls which day is numbered 1. Default (1): Sunday=1. Use 2 for Monday=1.
⚠️ Always check return_type before trusting weekend logic

With the default return_type, Saturday=7 and Sunday=1. With return_type=2, Saturday=6 and Sunday=7 — getting this backwards silently breaks weekend-detection formulas.

Examples

Example 1
Day number, Sunday-based (default)
=WEEKDAY(DATE(2026,6,22))

June 22, 2026 is a Monday, so this returns 2 under the default numbering.

Example 2
Day number, Monday-based
=WEEKDAY(DATE(2026,6,22),2)

Same date, but with return_type=2, Monday becomes 1 — so this also returns 1, just under different numbering logic.

Example 3
Flag a weekend
=IF(WEEKDAY(A2,2)>5,"Weekend","Weekday")

With return_type=2, Saturday=6 and Sunday=7, so anything above 5 is a weekend.

Example 4
Find the next Monday
=A2+(9-WEEKDAY(A2,2))

A common trick to roll a date forward to the next Monday.

Common mistakes

⚠️ Forgetting which return_type you used

Mixing return_type conventions across a workbook leads to inconsistent weekend/weekday logic — pick one and stay consistent.

FAQ

Is there an easier way to check for weekends?
NETWORKDAYS and WORKDAY already exclude weekends automatically for date-range calculations, without needing WEEKDAY directly.

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Related formulas

WEEKNUM NETWORKDAYS WORKDAY DAY