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 1999? Altersrechner

Your date of birth

Date of birth

Calculate age as of

Also show Korean age

Results

Total days: 9,950
Total weeks: 1,421
Total months: 326
Total hours: 238,800
Seconds lived: 0

1999 age range (2026)

	Alter
Alter nach dem Geburtstag (frühestes Datum im Jahr)	27
Alter vor dem Geburtstag (spätestes Datum im Jahr)	26

Browse 1999 by month

january 1999 february 1999 march 1999 april 1999 may 1999 june 1999 july 1999 august 1999 september 1999 october 1999 november 1999 december 1999

Example dates in 1999

Geburtsdatum	Aktuelles Alter	Calculator
1. Januar 1999	27	Open
15. Juni 1999	27	Open
11. September 1999	27	Open
31. Dezember 1999	26	Open

All dates in 1999 (sample)

Date	Page
1. Januar 1999	january-1-1999
15. Januar 1999	january-15-1999
31. Januar 1999	january-31-1999
1. Februar 1999	february-1-1999
15. Februar 1999	february-15-1999
28. Februar 1999	february-28-1999
1. März 1999	march-1-1999
15. März 1999	march-15-1999
31. März 1999	march-31-1999
1. April 1999	april-1-1999
15. April 1999	april-15-1999
30. April 1999	april-30-1999
1. Mai 1999	may-1-1999
15. Mai 1999	may-15-1999
31. Mai 1999	may-31-1999
1. Juni 1999	june-1-1999
15. Juni 1999	june-15-1999
30. Juni 1999	june-30-1999
1. Juli 1999	july-1-1999
15. Juli 1999	july-15-1999
31. Juli 1999	july-31-1999
1. August 1999	august-1-1999
15. August 1999	august-15-1999
31. August 1999	august-31-1999
1. September 1999	september-1-1999
15. September 1999	september-15-1999
30. September 1999	september-30-1999
1. Oktober 1999	october-1-1999
15. Oktober 1999	october-15-1999
31. Oktober 1999	october-31-1999
1. November 1999	november-1-1999
15. November 1999	november-15-1999
30. November 1999	november-30-1999
1. Dezember 1999	december-1-1999
15. Dezember 1999	december-15-1999
31. Dezember 1999	december-31-1999

Altersmeilensteine

Alter	Jahr erreicht
1	2000
5	2004
10	2009
13	2012
16	2015
18	2017
21	2020
25	2024
30	2029
40	2039
50	2049

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

1997 1998 1999 2000 2001