Age Calculator

Enter your birthdate and see your exact age plus fun stats.

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Calculate exact age in years, months and days

Date of birth

Reference date

In Excel and Google Sheets

The DATEDIF function calculates the difference between two dates in the unit you choose. Put the birth date in A2 and the reference date in B2 (or use TODAY() for the current date):

Full years of age:
=DATEDIF(A2, B2, "Y")

Remaining months (after whole years):
=DATEDIF(A2, B2, "YM")

Remaining days (after whole years and months):
=DATEDIF(A2, B2, "MD")

Total days lived:
=B2-A2

Day of the week (1 = Sunday … 7 = Saturday):
=WEEKDAY(A2)

Days until next birthday:
=IF(DATE(YEAR(B2),MONTH(A2),DAY(A2))>=B2,
    DATE(YEAR(B2),MONTH(A2),DAY(A2))-B2,
    DATE(YEAR(B2)+1,MONTH(A2),DAY(A2))-B2)

DATEDIF does not appear in Excel's function menu, but it works if you type it directly. Google Sheets supports it the same way. In localized Excel versions the function name may differ (e.g. SIFECHA in Spanish).

In SQL

Each engine has its own function. Given a table people with a column birth_date:

-- PostgreSQL — AGE()
SELECT
    birth_date,
    AGE(CURRENT_DATE, birth_date)                         AS age_interval,
    EXTRACT(YEAR FROM AGE(CURRENT_DATE, birth_date))      AS age_years,
    EXTRACT(MONTH FROM AGE(CURRENT_DATE, birth_date))     AS age_months,
    EXTRACT(DAY FROM AGE(CURRENT_DATE, birth_date))       AS age_days,
    CURRENT_DATE - birth_date                              AS total_days
FROM people;

AGE() returns a human-readable interval. EXTRACT pulls years or months from that interval.

-- MySQL — TIMESTAMPDIFF
SELECT
    birth_date,
    TIMESTAMPDIFF(YEAR, birth_date, CURDATE())   AS age_years,
    TIMESTAMPDIFF(MONTH, birth_date, CURDATE())
        - TIMESTAMPDIFF(YEAR, birth_date, CURDATE()) * 12
                                                  AS age_months,
    DATEDIFF(CURDATE(), birth_date)               AS total_days
FROM people;

TIMESTAMPDIFF calculates the difference in the unit you request: YEAR, MONTH, or DAY.

-- SQL Server — DATEDIFF
SELECT
    birth_date,
    DATEDIFF(YEAR, birth_date, GETDATE())
        - CASE WHEN DATEADD(YEAR,
              DATEDIFF(YEAR, birth_date, GETDATE()),
              birth_date) > GETDATE()
          THEN 1 ELSE 0 END                       AS age_years,
    DATEDIFF(DAY, birth_date, GETDATE())           AS total_days
FROM people;

DATEDIFF counts boundary crossings, so subtracting 1 when the birthday has not yet occurred gives the exact age.

About this age calculator

Pick your date of birth and an optional reference date (defaults to today) to see your exact age broken down into years, months, and days. The calculator also shows total days lived, weeks lived, your day of the week born on, and how many days until your next birthday — all computed with proper calendar math that handles leap years correctly.

The same date logic powers HR onboarding systems, insurance eligibility checks, and legal age verification. The tool includes the Excel DATEDIF function (which exists but is undocumented in modern Excel) and the PostgreSQL AGE() function so you can reproduce the calculation in a spreadsheet or a database query.

FAQ

How does the calculator handle leap years?

It uses calendar-based arithmetic, not a fixed 365.25-day year. February 29 birthdays are handled correctly: if the reference year is not a leap year, the birthday falls on March 1 for countdown purposes.

Is my date of birth stored anywhere?

No. The calculation runs entirely in your browser using JavaScript. Nothing is sent to any server — the date you enter never leaves your device.

Can I calculate someone else’s age on a specific date?

Yes. Enter their birthdate and change the reference date to any date you want. This is useful for checking age eligibility on a past or future date.