Quick example
Age from May 15, 1990 to August 22, 2026
The person has completed 36 years, 3 months, and 7 days. That is 435 complete months or 13,248 elapsed calendar days.
How it works
Age uses completed calendar units
Completed years
A year counts only after the calendar anniversary has been reached.
Remaining months
After full years, the calculator counts complete calendar months.
Remaining days
Days are counted from the last complete month boundary to the as-of date.
Total days
The exact date-only difference includes leap days but ignores clock time.
Leap-day convention
February 29 birthdays in non-leap years
For a next-birthday countdown, this calculator uses February 28 as the anniversary in a year without February 29. Legal age rules can differ by jurisdiction, so confirm the applicable rule for official purposes.
Common questions
Age calculator FAQ
How is age calculated?
It counts full years, full months after those years, and then the remaining calendar days.
How are February 29 birthdays handled?
The countdown uses February 28 in non-leap years. Official rules may differ.
Can I calculate age on another date?
Yes. Set the as-of date to any date on or after the birth date.