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 1977? Altersrechner

Your date of birth

Date of birth

Calculate age as of

Also show Korean age

Results

Total days: 17,985
Total weeks: 2,569
Total months: 590
Total hours: 431,640
Seconds lived: 0

1977 age range (2026)

	Alter
Alter nach dem Geburtstag (frühestes Datum im Jahr)	49
Alter vor dem Geburtstag (spätestes Datum im Jahr)	48

Browse 1977 by month

january 1977 february 1977 march 1977 april 1977 may 1977 june 1977 july 1977 august 1977 september 1977 october 1977 november 1977 december 1977

Example dates in 1977

Geburtsdatum	Aktuelles Alter	Calculator
1. Januar 1977	49	Open
15. Juni 1977	49	Open
11. September 1977	49	Open
31. Dezember 1977	48	Open

All dates in 1977 (sample)

Date	Page
1. Januar 1977	january-1-1977
15. Januar 1977	january-15-1977
31. Januar 1977	january-31-1977
1. Februar 1977	february-1-1977
15. Februar 1977	february-15-1977
28. Februar 1977	february-28-1977
1. März 1977	march-1-1977
15. März 1977	march-15-1977
31. März 1977	march-31-1977
1. April 1977	april-1-1977
15. April 1977	april-15-1977
30. April 1977	april-30-1977
1. Mai 1977	may-1-1977
15. Mai 1977	may-15-1977
31. Mai 1977	may-31-1977
1. Juni 1977	june-1-1977
15. Juni 1977	june-15-1977
30. Juni 1977	june-30-1977
1. Juli 1977	july-1-1977
15. Juli 1977	july-15-1977
31. Juli 1977	july-31-1977
1. August 1977	august-1-1977
15. August 1977	august-15-1977
31. August 1977	august-31-1977
1. September 1977	september-1-1977
15. September 1977	september-15-1977
30. September 1977	september-30-1977
1. Oktober 1977	october-1-1977
15. Oktober 1977	october-15-1977
31. Oktober 1977	october-31-1977
1. November 1977	november-1-1977
15. November 1977	november-15-1977
30. November 1977	november-30-1977
1. Dezember 1977	december-1-1977
15. Dezember 1977	december-15-1977
31. Dezember 1977	december-31-1977

Altersmeilensteine

Alter	Jahr erreicht
1	1978
5	1982
10	1987
13	1990
16	1993
18	1995
21	1998
25	2002
30	2007
40	2017
50	2027

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

1975 1976 1977 1978 1979