Age Calculator
Calculate your age in years, months and days from your birth date. See total days lived, your birth weekday and the countdown to your next birthday.
The example below uses today’s UTC date.
Age in years, months and days
January 1, 2000 → October 21, 2026
26 years, 9 months, 20 days
| Measure | Value |
|---|---|
| Total days | 9,790 |
| Weeks and remaining days | 1,398 weeks, 4 days |
| Complete months | 321 |
| Birth weekday | Saturday |
| Next birthday | |
| Day of the week | Friday |
| Days until your birthday | 72 |
How the calculation works
Age is the number of complete calendar months since birth, split into years and months, plus the remaining days. Months are anchored to the birth date and clamped to the last day when necessary. A February 29 birthday falls on February 28 in a non-leap year. Today’s birthday has zero days remaining.
Frequently asked questions
How is age calculated for a February 29 birthday?
This calculator uses February 28 as the anniversary in non-leap years and February 29 in leap years. This is a calendar convention; rules for legal age can differ.
Is age in months the total days divided by 30?
No. Complete months follow the calendar because months have 28, 29, 30 or 31 days. For example, January 31 to February 28 in a non-leap year is one complete month under the clamping rule.
Can I calculate age on a past or future date?
Yes. Change the reference date to any date on or after the birth date. The next birthday is measured from that reference date, not necessarily from today.
Do time zones or daylight saving change the age?
The calculator compares calendar dates, without birth times. Date arithmetic uses UTC so daylight saving cannot add or remove a day. With JavaScript enabled, the default reference date is today on your device.