Dates and time
Calculate age by the calendar.
Use a birth date and any comparison date to find completed years, months, days, total elapsed days, and time until the next birthday.
Your result
Age will appear here.
Enter a birth date. The comparison date defaults to today.
Calendar age
Total days
Complete weeks
Next birthday
How calendar age is counted
Age counts completed calendar years first, then completed calendar months, then remaining days. Months cannot be treated as a fixed number of days because they vary from 28 to 31 days.
For a February 29 birth date, this calculator uses February 28 in non-leap years for elapsed calendar calculations. Legal treatment can vary by jurisdiction and purpose.
Total days are measured as date-to-date calendar days without using the time of day, which avoids daylight-saving-time shifts.
This tool provides general calendar calculations and should not be used as a substitute for an official age determination in legal or eligibility matters.
Calendar age is not a duration in hours
A calendar age reports completed years, months, and days. Because months have different lengths, the same number of elapsed days can represent different calendar descriptions.
Choose the comparison date
Use today for a current age, or choose a future date for planning. The result does not use the time of day, time zone, or birth time.
Know the boundary
Legal age, eligibility, insurance, school placement, and benefits may use rules defined by an agency or jurisdiction. Use an official determination when the result has legal consequences.
Keep calculating
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