How to Calculate Age in Excel from a Date of Birth
Excel has no AGE() function, so turning a date of birth into an age means reaching for DATEDIF — an undocumented function with three different arguments for years, months, and days. Here's the formula, and a one-click alternative.
Last updated: September 2026
| Date of birth | Age (as of today) | |
|---|---|---|
| 1990-03-10 | → | 34 |
| 2001-12-31 | → | 22y 5m 1d |
Method 1 — DATEDIF for whole years
=DATEDIF(A2, TODAY(), "y")returns completed years — the everyday "age".- Swap
TODAY()for a cell if you need the age "as of" a specific date. - Copy down. It works, though Excel won't autocomplete DATEDIF and warns if you fat-finger it.
Method 2 — years, months & days
For a full breakdown you chain three DATEDIFs:
=DATEDIF(A2,TODAY(),"y")&"y "&DATEDIF(A2,TODAY(),"ym")&"m "&DATEDIF(A2,TODAY(),"md")&"d"- Accurate, but long, and easy to mistype. For a decimal age,
=YEARFRAC(A2, TODAY())is the shortcut.
The 1-click way — Tellsheet
Age & Tenure turns a birth-date (or hire-date) column into age with no formula. Choose whole years, a full 34y 2m 5d breakdown, or decimal years to the precision you pick — measured as of today or a date you enter. It reads real Excel dates and text dates alike, with a day-first switch, and writes to a new column beside the source. Pairs with Date Difference and Extract Date Parts.
Frequently asked questions
How do I calculate age from a date of birth?
=DATEDIF(dob, TODAY(), "y") for whole years, or Tellsheet's Age & Tenure for the whole column in one click.
Is there an age function in Excel?
No — use DATEDIF or YEARFRAC, or Tellsheet's Age & Tenure.
Can I get years, months and days?
Yes — the "years, months & days" mode returns 34y 2m 5d.
Can I measure age as of a past date?
Yes — enter an "as of" date instead of leaving it blank for today.
Related Excel guides
Turn birth dates into ages in one click
Age & Tenure gives whole years, y/m/d, or decimal years — no DATEDIF — inside Excel.
Get Tellsheet free See pricing