Excel DAY Function
DAY returns the day-of-month number from an Excel date.
Use it to identify due-day rules, pull the date number from timestamps, build date labels, or test whether records fall on a particular day of the month.
DAY syntax & arguments
Syntax
=DAY(serial_number)
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1
serial_number
RequiredThe Excel date value, cell reference, or formula result whose day-of-month number should be returned.
Example
=DAY(A2)
Return the day-of-month number from the date in A2.
DAY caveats
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The source should be a real date
DAY works most reliably with a date cell, an Excel date serial number, or a date built with DATE.
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DAY is not the day of week
DAY returns the calendar day inside the month. For example, March 15 returns
15, not a weekday number. -
Formatted dates still use the underlying date
A date displayed as
15-Marand the same date displayed as3/15/2026return the same DAY result. -
Text dates can be ambiguous
Typed text such as
"03/04/2026"may be interpreted differently across regional settings, so build dates with DATE when consistency matters.
Splitting a date into parts? Use DAY with MONTH and YEAR when formulas need separate calendar components.
Intro DAY practice problem
Solve the intro problem directly here, or open it on its own page.
Advanced DAY practice problems
Use DAY alongside other Excel functions in realistic, less-prescriptive challenges.
