How to Use DAY, MONTH, and YEAR Functions in Excel (Video in Khmer)

Hello everyone! Today I show you very easy step-by-step how to use DAY(), MONTH(), and YEAR() functions in Microsoft Excel.

If you have a full date like 2026-09-15 in your spreadsheet and you want to extract only the day number, month number, or year number into separate columns, these 3 formulas help you very fast!

📚 Related Tutorial: Want to get current date automatically? Check out How to Use NOW() and TODAY() in Excel!

📊 Quick Comparison: DAY vs MONTH vs YEAR

Function	What It Extracts	Result Example	Best Used For
`DAY`	Day number of the month (1 to 31)	`15`	Extracting day from birth date or invoice date
`MONTH`	Month number of the year (1 to 12)	`9` (September)	Grouping sales or reports by month
`YEAR`	4-digit year number (1900 to 9999)	`2026`	Filtering data by year

🛠️ 1. How to Use DAY Function in Excel

The DAY function extracts the day of the month from a date cell (returns a number from 1 to 31).

Formula Syntax:

=DAY(serial_number)

Simple Example:

If cell A2 has date 2026-09-15:

=DAY(A2)

Result: 15

🛠️ 2. How to Use MONTH Function in Excel

The MONTH function extracts the month number from a date cell (returns a number from 1 to 12, where 1 = January and 12 = December).

Formula Syntax:

=MONTH(serial_number)

Simple Example:

If cell A2 has date 2026-09-15:

=MONTH(A2)

Result: 9 (September)

🛠️ 3. How to Use YEAR Function in Excel

The YEAR function extracts the 4-digit year number from a date cell.

Formula Syntax:

=YEAR(serial_number)

Simple Example:

If cell A2 has date 2026-09-15:

=YEAR(A2)

Result: 2026

💡 Combine DAY, MONTH, and YEAR Together (DATE Function)

If you have separate columns for Year (C2), Month (B2), and Day (A2), you can combine them back into a real Excel date using =DATE():

=DATE(year, month, day)
=DATE(C2, B2, A2)

Result: 2026-09-15

📚 Related Tutorial: Learn more foundational formulas in our guide on Top 15 Basic Excel Formulas for Beginners ↗!

💡 Pro Tips for Date Functions

Cell Must Be Real Date: If DAY(), MONTH(), or YEAR() gives #VALUE! error, your date cell might be saved as text! Convert it to Date format first.
Combine with TODAY(): Want to find current month number? Use =MONTH(TODAY()).
Format Month Name: If you want to show month name like "September" instead of number 9, use =TEXT(A2, "mmmm").