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.

Age Calculator for December Birth Dates

December by year

December 1926 December 1927 December 1928 December 1929 December 1930 December 1931 December 1932 December 1933 December 1934 December 1935 December 1936 December 1937 December 1938 December 1939 December 1940 December 1941 December 1942 December 1943 December 1944 December 1945 December 1946 December 1947 December 1948 December 1949 December 1950 December 1951 December 1952 December 1953 December 1954 December 1955 December 1956 December 1957 December 1958 December 1959 December 1960 December 1961 December 1962 December 1963 December 1964 December 1965 December 1966 December 1967 December 1968 December 1969 December 1970 December 1971 December 1972 December 1973 December 1974 December 1975 December 1976 December 1977 December 1978 December 1979 December 1980 December 1981 December 1982 December 1983 December 1984 December 1985 December 1986 December 1987 December 1988 December 1989 December 1990 December 1991 December 1992 December 1993 December 1994 December 1995 December 1996 December 1997 December 1998 December 1999 December 2000 December 2001 December 2002 December 2003 December 2004 December 2005 December 2006 December 2007 December 2008 December 2009 December 2010 December 2011 December 2012 December 2013 December 2014 December 2015 December 2016 December 2017 December 2018 December 2019 December 2020 December 2021 December 2022 December 2023 December 2024 December 2025 December 2026

Other months

january february march april may june july august september october november