How to use this age calculator
- Enter your date of birth using the calendar picker.
- Leave Age on this date as today to answer “how old am I now,” or pick another day (past or future) to see age on that date.
- Review exact age in years, months, and days; total days lived; weekday you were born; next birthday; and days until that birthday.
- Use Copy link to bookmark this scenario or send the same dates to someone else.
Example: date of birth March 15, 1990
With birth date 1990-03-15 and age on today, you might see something like 36 years, 7 months, 15 days, depending on the current calendar date. Total days lived counts every calendar day from birth through the as-of date. Next birthday shows the upcoming March 15 and how many days remain—useful for planning, forms, or curiosity.
Change the as-of date to a wedding, graduation, or contract start to answer “how old was I then?” without mental math.
Calendar age vs. decimal age
This tool shows calendar age (years, months, days), the format used on IDs, school forms, and “happy birthday” messages. Some sites show age as a decimal (e.g. 36.7 years); that is a different calculation. For the span between any two dates without a birth date, use the date difference calculator.
Leap years and February 29
Total days lived includes leap days. For next-birthday logic, Feb 29 births in non-leap years typically celebrate on Feb 28 or Mar 1; this page follows common next-occurrence rules so the countdown stays sensible.
When to use other date tools
Age is for birth date → how old on a given day. To measure days between two arbitrary dates (project timelines, leases), use the date difference calculator. For “how many days until Christmas or my trip,” try the days until calculator. To move a deadline by 30 days or 6 months, use add/subtract days from a date. All date tools are listed on date & time calculators.
Frequently asked questions
How old am I today?
Enter your birth date and leave Age on this date as today. Exact age updates in years, months, and days, with total days lived below.
How do you calculate age from date of birth?
Full years from birth to the as-of date, then remaining months, then days. Use the exact age line on this page—not total days ÷ 365.
How old was I on a specific date?
Set Age on this date to that day. Useful for forms, “how old was I at graduation,” or future planning.
If I was born in 1990, how old am I now?
Enter your full birth date (e.g. 1990-03-15) and keep the as-of date as today. Years, months, and days update daily until your next birthday.
Age calculator vs date difference calculator?
Age needs a birth date and answers “how old on this day.” Date difference is for any start/end pair (projects, leases) without a birth date.
Does leap year or February 29 affect my age?
Yes—each calendar day counts, including leap days. Feb 29 births use standard next-birthday handling in non-leap years.
Why might my age differ from another website by one day?
We ignore birth time and timezone—calendar dates only. Use the same as-of date on both tools when comparing.
When will I turn 18 or another milestone age?
Try the age milestone calculator—birth date + target age (18, 21, 65) shows the date you reach that age and days remaining.
Can I share my calculation?
Yes. Copy link saves birth and as-of dates in the URL so anyone can reopen the same age breakdown.