Age is calculated by comparing your date of birth with the current date (or a specified end date). The calculation accounts for leap years and varying month lengths. We subtract the birth year from the current year, then adjust for months and days. If you haven't reached your birthday yet this year, one year is subtracted. The precise algorithm ensures accuracy down to the exact day, correctly handling edge cases like February 29 birthdays in non-leap years.

Chronological age is the exact number of years, months, and days since your birth — this is what our calculator provides. Biological age refers to how old your body appears based on various health markers such as telomere length, DNA methylation, organ function, and lifestyle factors. Some people may have a biological age younger or older than their chronological age depending on diet, exercise, genetics, and environmental factors. This tool calculates chronological age only.

Leap years add an extra day (February 29) every 4 years, with exceptions for century years not divisible by 400. Our calculator fully accounts for all leap years when computing total days, weeks, and hours between dates. If you were born on February 29 (a leap day), your birthday is celebrated on February 28 or March 1 in non-leap years, and the calculator correctly handles this by adjusting the annual birthday marker. The total day count always reflects the actual number of elapsed calendar days including all leap days.

Yes! You can use the Date Difference tab to calculate the exact duration between any two dates — past, present, or future. This is useful for calculating the age of historical figures at specific events, determining how old someone was on a particular date, or measuring the time span between any two calendar dates. The calculator handles dates from year 1 onwards, though extreme historical dates should account for calendar system changes (such as the switch from Julian to Gregorian calendars in 1582).

In Excel or Google Sheets, you can use the DATEDIF function: =DATEDIF(birthdate, TODAY(), "Y") returns full years. For complete age in years, months, and days, use:
=DATEDIF(A1, TODAY(), "Y") & " years, " & DATEDIF(A1, TODAY(), "YM") & " months, " & DATEDIF(A1, TODAY(), "MD") & " days"
Replace A1 with the cell containing the birth date. The "YM" parameter gives remaining months after full years, and "MD" gives remaining days after full months. Our online calculator provides the same precision instantly without any formula knowledge needed.

The total months figure counts every full calendar month between your birth date and today. Since months have different lengths (28-31 days), and your birthday may fall on a day that doesn't exist in every month (like the 31st), the total month count is calculated by counting complete month boundaries crossed, not by simply multiplying years by 12. This gives a more accurate representation of elapsed time. The same principle applies to total weeks (each exactly 7 days) and total days (each exactly 24 hours).

Our age calculator automatically determines your Western zodiac sign (sun sign) based on your date of birth using standard astrological date ranges. The 12 signs are: Aries (Mar 21-Apr 19), Taurus (Apr 20-May 20), Gemini (May 21-Jun 20), Cancer (Jun 21-Jul 22), Leo (Jul 23-Aug 22), Virgo (Aug 23-Sep 22), Libra (Sep 23-Oct 22), Scorpio (Oct 23-Nov 21), Sagittarius (Nov 22-Dec 21), Capricorn (Dec 22-Jan 19), Aquarius (Jan 20-Feb 18), and Pisces (Feb 19-Mar 20). This is a fun additional feature alongside the precise age calculation.