How do I calculate my age from my date of birth?

Subtract your birth year from the current year. If your birthday has not happened yet this year, subtract one more year from that total. Then count the months and days separately using the same subtract-and-borrow method. This tool does all of that automatically. You just get the finished answer.

Can I calculate my age on a specific date?

Yes. Instead of leaving the calculate-as-of field on today, pick any date, past or future, and the tool works out your age as of that day. Use this for school enrollment cutoffs, immigration age requirements, or figuring out how old you will be on a future date like a wedding or retirement.

How does this handle leap years?

Leap years are built into the calendar math, not added as an afterthought. If someone's birthday is February 29, this tool treats it as February 28 in non-leap years for counting elapsed years, the same convention most legal and administrative systems use, while still calculating the exact day count correctly underneath.

What is chronological age?

Chronological age is the time that has passed since birth, measured in the calendar: years, months, and days. It is different from biological age, which estimates how old a body seems rather than how long a person has actually been alive. When a form or a doctor asks for your age, chronological age is what they mean.

How is Korean age different from international age?

Korean age starts at one, not zero, on the day someone is born, and everyone's age increases together on New Year's Day instead of on individual birthdays. Depending on birth month, that can put Korean age one or two years ahead of the international age most of the world uses. Toggle Also show Korean age to see both numbers at once.

How do I calculate age difference between two people?

Switch to the Age Difference tab, enter both birth dates, and the calculator returns the gap as years, months, and days, plus a flat day count if you need one number instead of three. It works the same way whether the gap is a few months or several decades.

How accurate is this online tool?

It is accurate to the day, using real calendar date math rather than a simplified days-divided-by-365 estimate. Leap years, varying month lengths, and the borrow-a-month logic are all handled correctly. The one thing it cannot account for is a wrong birth date typed in.

How do I calculate age in Excel?

Put the birth date in a cell, then wrap it in Excel's DATEDIF function with "Y", "YM", and "MD" as the unit arguments to pull out years, months, and days separately. The full formula is in the Excel section above. It is the same calendar-based approach this tool uses, just typed out manually.

Yes. Everything runs in your browser using JavaScript. Your birth date never leaves your device. There are no servers processing your information and no account required. You can disconnect from the internet after loading the page and the calculator still works.

Can I use this for my pet?

Yes. Click the Pet Age tab, choose dog or cat, and enter how many years old your pet is. The tool converts to human-equivalent age using the standard veterinary formula, not the old seven dog years equals one human year shortcut.

Wie alt ist jemand, geboren 1979? Altersrechner

Your date of birth

Date of birth

Calculate age as of

Also show Korean age

Results

Total days: 17,255
Total weeks: 2,465
Total months: 566
Total hours: 414,120
Seconds lived: 0

1979 age range (2026)

	Alter
Alter nach dem Geburtstag (frühestes Datum im Jahr)	47
Alter vor dem Geburtstag (spätestes Datum im Jahr)	46

Browse 1979 by month

january 1979 february 1979 march 1979 april 1979 may 1979 june 1979 july 1979 august 1979 september 1979 october 1979 november 1979 december 1979

Example dates in 1979

Geburtsdatum	Aktuelles Alter	Calculator
1. Januar 1979	47	Open
15. Juni 1979	47	Open
11. September 1979	47	Open
31. Dezember 1979	46	Open

All dates in 1979 (sample)

Date	Page
1. Januar 1979	january-1-1979
15. Januar 1979	january-15-1979
31. Januar 1979	january-31-1979
1. Februar 1979	february-1-1979
15. Februar 1979	february-15-1979
28. Februar 1979	february-28-1979
1. März 1979	march-1-1979
15. März 1979	march-15-1979
31. März 1979	march-31-1979
1. April 1979	april-1-1979
15. April 1979	april-15-1979
30. April 1979	april-30-1979
1. Mai 1979	may-1-1979
15. Mai 1979	may-15-1979
31. Mai 1979	may-31-1979
1. Juni 1979	june-1-1979
15. Juni 1979	june-15-1979
30. Juni 1979	june-30-1979
1. Juli 1979	july-1-1979
15. Juli 1979	july-15-1979
31. Juli 1979	july-31-1979
1. August 1979	august-1-1979
15. August 1979	august-15-1979
31. August 1979	august-31-1979
1. September 1979	september-1-1979
15. September 1979	september-15-1979
30. September 1979	september-30-1979
1. Oktober 1979	october-1-1979
15. Oktober 1979	october-15-1979
31. Oktober 1979	october-31-1979
1. November 1979	november-1-1979
15. November 1979	november-15-1979
30. November 1979	november-30-1979
1. Dezember 1979	december-1-1979
15. Dezember 1979	december-15-1979
31. Dezember 1979	december-31-1979

Altersmeilensteine

Alter	Jahr erreicht
1	1980
5	1984
10	1989
13	1992
16	1995
18	1997
21	2000
25	2004
30	2009
40	2019
50	2029

So wird berechnet

Das Kalenderalter zählt vollendete Geburtstage. Grob: Referenzjahr minus Geburtsjahr, minus 1 wenn der Geburtstag noch aussteht.
Genaues Alter = Jahre + Monate + Tage zwischen Geburts- und Referenzdatum, mit korrekter Monatslänge.

Age = Reference date − Birth date

Weeks ≈ total days ÷ 7. Hours = total days × 24. Minutes = total hours × 60 (exact for whole-day spans).

Nahe Geburtsjahre

1977 1978 1979 1980 1981