Enter the date of birth
Age
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How to use the age calculator
When a form asks for your age, it can differ by one year depending on whether your birthday has passed. This tool calculates your exact age from a date of birth and a reference date, and also shows the zodiac sign, Chinese zodiac, days lived and days to your next birthday.
How to use it
Enter a date of birth to get today's age. To find the age as of a specific day, change the reference date — handy for an application cut-off or the age on an event day.
Exact age vs other systems
The commonly used figure is your full-year age (0 at birth, +1 each birthday). Some traditions use different counts, such as the East Asian "counted age", where a person is 1 at birth. This tool shows the standard full-year age.
Frequently asked questions
How is age calculated?+
It counts how many birthdays have passed from the date of birth up to the reference date (today by default).
It is the common full-year age.
It is the common full-year age.
How are the zodiac and Chinese zodiac determined?+
The Western zodiac comes from the month and day using the usual cut-off dates.
The Chinese zodiac comes from the birth year's 12-year animal cycle.
The Chinese zodiac comes from the birth year's 12-year animal cycle.
How do you count days lived?+
It is the number of calendar days between the date of birth and the reference date, on the Gregorian calendar, including leap years.
Can I use a reference date other than today?+
Yes. Change the reference date to find the age as of any specific day, such as an application cut-off or an event date.
Is my date of birth stored?+
No. All calculation happens in your browser, and the date of birth you enter is never sent to or stored on a server.
Method
・Age = number of birthdays reached by the reference date (ref year − birth year, minus 1 if the birthday has not yet occurred)
・Chinese zodiac = birth year's animal in the 12-year cycle ((year − 4) mod 12)
・Western zodiac = month and day mapped to the usual sign cut-offs
・Calendar: Gregorian, including leap years.
・Age = number of birthdays reached by the reference date (ref year − birth year, minus 1 if the birthday has not yet occurred)
・Chinese zodiac = birth year's animal in the 12-year cycle ((year − 4) mod 12)
・Western zodiac = month and day mapped to the usual sign cut-offs
・Calendar: Gregorian, including leap years.
Please note
This site does not represent any organization and does not guarantee the accuracy of the results. Age handling for schooling or various systems varies by law and rules. For official procedures, confirm the prescribed basis.
This site does not represent any organization and does not guarantee the accuracy of the results. Age handling for schooling or various systems varies by law and rules. For official procedures, confirm the prescribed basis.