Find your exact age in years, months, and days, plus how many days you have been alive and when your next birthday lands.
Defaults to today's date. Change it to find an age (yours, or anyone else's) on any past or future date.
The years, months, and days figure counts one full year for every birthday that has passed between your date of birth and the "as of" date, then counts remaining full months, then whatever days are left over - the same way age is stated on most official forms. Total days and weeks lived are a straight count of every day between the two dates, including any February 29ths your life has included. Days until your next birthday finds the next time your birth month and day occur on or after the "as of" date.
For someone born on January 15, 1995 (a Sunday), calculated as of September 13, 2026, this works out to 31 years, 7 months, and 29 days old. That is 11,564 total days lived, or exactly 1,652 weeks, with 124 days left until their next birthday on January 15, 2027.
How exactly is age calculated here?
The calculator counts every full year between your birth date and the "as of" date, then the full months left over, then the remaining days - the same order most official age statements use. This avoids the rounding errors you get from simply dividing total days by 365.
Why isn't my total days lived a round number?
Because months have different lengths and roughly every fourth year has an extra day (February 29). Total days lived simply counts every calendar day between your birth date and the "as of" date, leap days included.
Can I calculate age as of a date other than today?
Yes. Change the "as of" field to any date - a past date for a historical calculation, or a future date to see how old you (or someone else) will be. The "as of" date should not be earlier than the date of birth.
Does this account for leap years?
Yes. The day and week totals include every February 29 that falls in the range, and the years/months/days breakdown correctly handles the shorter and longer Februaries when rolling over month boundaries.
Can I use this for someone else, or for a pet?
Yes. Enter any birth date you like - the math works the same regardless of whose age you are calculating.
Why does total months lived look different from years times twelve plus months?
It shouldn't - total months lived is the same figure as your years multiplied by twelve, plus the leftover months shown in the main result, just given as a single number. Any difference of one usually means the leftover days have not yet reached a full extra month.
What if I only know the month and year I (or they) were born?
Use the 1st of that month as a stand-in date of birth. Your years and months will still be accurate, and the day count will be off by at most a few weeks - close enough for a rough estimate, though not for anything requiring an exact date.