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.

Quel âge a quelqu'un né en 1940 ?

Your date of birth

Date of birth

Calculate age as of

Also show Korean age

Results

Total days: 31,499
Total weeks: 4,499
Total months: 1,034
Total hours: 755,976
Seconds lived: 0

1940 age range (2026)

	Âge
Âge après l'anniversaire (premier jour de l'année)	86
Âge avant l'anniversaire (dernier jour de l'année)	85

Browse 1940 by month

january 1940 february 1940 march 1940 april 1940 may 1940 june 1940 july 1940 august 1940 september 1940 october 1940 november 1940 december 1940

Example dates in 1940

Date de naissance	Âge actuel	Calculator
1 janvier 1940	86	Open
15 juin 1940	86	Open
11 septembre 1940	86	Open
31 décembre 1940	85	Open

All dates in 1940 (sample)

Date	Page
1 janvier 1940	january-1-1940
15 janvier 1940	january-15-1940
31 janvier 1940	january-31-1940
1 février 1940	february-1-1940
15 février 1940	february-15-1940
29 février 1940	february-29-1940
1 mars 1940	march-1-1940
15 mars 1940	march-15-1940
31 mars 1940	march-31-1940
1 avril 1940	april-1-1940
15 avril 1940	april-15-1940
30 avril 1940	april-30-1940
1 mai 1940	may-1-1940
15 mai 1940	may-15-1940
31 mai 1940	may-31-1940
1 juin 1940	june-1-1940
15 juin 1940	june-15-1940
30 juin 1940	june-30-1940
1 juillet 1940	july-1-1940
15 juillet 1940	july-15-1940
31 juillet 1940	july-31-1940
1 août 1940	august-1-1940
15 août 1940	august-15-1940
31 août 1940	august-31-1940
1 septembre 1940	september-1-1940
15 septembre 1940	september-15-1940
30 septembre 1940	september-30-1940
1 octobre 1940	october-1-1940
15 octobre 1940	october-15-1940
31 octobre 1940	october-31-1940
1 novembre 1940	november-1-1940
15 novembre 1940	november-15-1940
30 novembre 1940	november-30-1940
1 décembre 1940	december-1-1940
15 décembre 1940	december-15-1940
31 décembre 1940	december-31-1940

Étapes d'âge

Âge	Année atteinte
1	1941
5	1945
10	1950
13	1953
16	1956
18	1958
21	1961
25	1965
30	1970
40	1980
50	1990

Comment c'est calculé

L'âge en années compte les anniversaires complets. Estimation : année de référence − année de naissance, moins 1 si l'anniversaire n'a pas encore eu lieu.
Âge exact = années + mois + jours entre la naissance et la date de référence, avec emprunt sur le mois précédent si besoin.

Age = Reference date − Birth date

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

Années proches

1938 1939 1940 1941 1942