Date & Time Operations Last updated: 2026-08-20

How to Calculate Age from Date of Birth in Excel & Google Sheets

Calculate current age in full completed years, exact decimal age, or years and months using DATEDIF and YEARFRAC formulas.

Quick Answer & Formula

Excel Sheets Beginner

=DATEDIF(Birth_Date, TODAY(), "Y") | =YEARFRAC(Birth_Date, TODAY(), 1)

To calculate current age in completed years: =DATEDIF(Birth_Date, TODAY(), "Y"). To calculate exact decimal age (e.g. 34.6 yrs): =YEARFRAC(Birth_Date, TODAY(), 1).

How to Calculate Age from Date of Birth in Excel & Google Sheets

Accurately computing customer, patient, or employee age from their date of birth is essential for compliance, insurance underwriting, and demographic reporting.

1. Completed Age in Years (The Standard Formula)

=DATEDIF(B2, TODAY(), "Y")

2. Age in Years and Months (e.g. “32 years, 4 months”)

=DATEDIF(B2, TODAY(), "Y") & " years, " & DATEDIF(B2, TODAY(), "YM") & " months"

3. Decimal Age for Statistical Modeling

=YEARFRAC(B2, TODAY(), 1)

Example: Born 05/20/1990 evaluated on 08/20/2026 returns 36.25 years.

Frequently Asked Questions

Why should I not calculate age as =(TODAY() - DOB) / 365.25?

Dividing by 365.25 causes off-by-one errors on birthdays due to leap year spacing. DATEDIF evaluates the true calendar anniversary and is 100% accurate.