DAY Function in Excel: Day of the Month

⏱ 1 min readUpdated 28 September 2026

DateLevel: BeginnerAvailable in: Excel 2007+

In this article
  1. Syntax
  2. Examples
  3. Example 1
  4. Example 2
  5. Common errors and fixes
  6. Related functions

DAY returns 1–31 from a date. Pair it with YEAR and MONTH to rebuild or test dates.

Syntax

=DAY(serial_number)
Argument What it means
serial_number A real date, not text.

Examples

Example 1

=IF(DAY(A2)<=15, "First half", "Second half")

Split invoices by half-month.

Example 2

=DAY(EOMONTH(A2,0))

Number of days in that month.

Common errors and fixes

You see Why, and the fix
#VALUE! Text Excel cannot read as a date, e.g. 31/12/2018 on a PC set to US format.

MONTH · YEAR · EOMONTH

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