Date & time · Calendar age
Exactly how old, in calendar terms.
Compare a birth date with any date to get years, months, days, total time and the next birthday.
Dates
Age is counted in calendar years, months and days.
Choose a birth date that is on or before the comparison date.
Age is calculated using calendar dates, not the time of day. February 29 birthdays are treated as February 28 in non-leap years and on February 28 regardless of leap year.
Good to know
The result is a guide, not a guarantee.
This calculator runs entirely in your browser. Check the assumptions, keep the inputs realistic, and use the result as a starting point for a decision.
Calendar-day calculation. Time zones and birth times are ignored.
How is age in years, months and days counted?
The calculator advances from the birth date by whole years, then whole months, and counts the remaining days. It handles month-end dates and leap years rather than dividing total days by 365.
How are February 29 birthdays handled?
A February 29 birthday is treated as February 28 for age and next-birthday calculations. Use the comparison date field if you need a different convention.
What is the next birthday countdown?
It is the number of calendar days from the comparison date to the next birthday. A result of zero means the birthday is on the comparison date.
Does the result include the time of day?
No. Dates are treated as whole calendar days. Birth time and time zone are not part of the calculation.