Excel DAY Function (Day of Month) – Examples & Practice
Practice the Excel DAY function online with an interactive grid, instant feedback, and clear formula help.
Instruction
Extract only the day-of-month number from date in A2.
Formula Syntax
=DAY(serial_number)
- serial_number: A date value Excel recognizes, usually a serial or a cell reference.
What it does
DAY extracts the day-of-month number from a date serial. It is commonly combined with MONTH and YEAR for parsing and reporting.
Excel DAY Function Examples
Extract day number
=DAY(A2)
Returns the day-of-month from a date serial.
date-calendar.xlsx
| A | B | |
|---|---|---|
| 1 | Date | Offset Months |
| 2 | 2026-01-15 | 0 |
| 3 | 2026-02-28 | 1 |
| 4 | 2026-03-31 | -1 |
| 5 | 2026-07-04 | 2 |
| 6 | 2026-12-20 | 3 |
| 7 | Output |
Input Formula
Need Help?
Tips
- Keep source dates as true serials, not text.
- Document month-end policies separately from DAY logic.
- Use DATE to reconstruct dates after splitting.
DAY Function Use Cases
- Billing cycles tied to day-of-month
- Birthday and anniversary logic
- Splitting imported timestamps
- QA checks on date columns
- Pair with MONTH/YEAR for composite keys
Common mistakes - DAY function not working
- Using DAY on text that only looks like a date
- Expecting weekday information from DAY
- Mixing UTC vs local assumptions without documentation
- Off-by-one when combining with month-end rules
- Forgetting DATE() when parts are separate cells
FAQ
Does DAY work on text dates?
Coercion rules apply; valid date serials are safest.
DAY vs WEEKDAY?
DAY returns 1–31; WEEKDAY returns day-of-week codes.
Can DAY be used in birthdays?
Yes, often combined with MONTH for annual reminders.
What does DAY return for time-only cells?
Time-only values may behave like a base date; validate inputs.
Is DAY locale-dependent?
The number is the calendar day; display formats are separate.
Comparison
| Function | Part extracted |
|---|---|
| DAY | Day of month |
| MONTH | Month number |
| YEAR | Year number |
Example
=DAY(A2)
Advanced examples
Day-based flags
=IF(DAY(A2)>=25, "Late cycle", "Normal") illustrates simple day thresholds (tune rules for your business).