Calculating a person's age from their birthday is a common task, especially in HR or data management. While it seems simple, doing it accurately requires a special, "hidden" Excel function: DATEDIF.
The DATEDIF Formula
This is the most reliable formula to calculate age in full years:
=DATEDIF(A1, TODAY(), "Y")
How it works:
- A1: The cell with the date of birth (e.g., 1/15/1990).
- TODAY(): A function that returns the current date, ensuring the calculation is always up-to-date.
- "Y": This unit tells the function to count the number of complete years between the two dates.
You can also calculate age in months ("M") or days ("D").
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