Find an exact age in years, months, and days from a date of birth — as of today or any date you choose.
Total days lived
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Days to next birthday
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Defaults to today; change it to find age on any date.
This calculator breaks the gap between a birth date and a reference date into calendar years, months, and days, the way people actually state an age. Because month lengths and leap years vary, it borrows days from the correct preceding month rather than assuming 30-day months, so the count stays exact across February and leap years. Leave the second field on today for a current age, or set it to a past or future date to answer questions like age at a wedding or on a school cut-off day.
Someone born January 1, 2000, measured as of March 1, 2020, is 20 years, 2 months, and 0 days old. That is 7,365 total days lived, with 306 days remaining until their next birthday.
The "age as of" field is what separates a birthday countdown from a historical age. Set it to a future date and you get how old someone will be then; set it to a past date and you get how old they were on that day — useful for eligibility and cut-off dates.
How are months and days counted exactly?
The calculator subtracts calendar components and, when the day-of-month goes negative, borrows the real number of days from the previous month (28, 29, 30, or 31). This is why the result can read "2 months, 0 days" rather than an approximate decimal.
Does it handle leap years and February 29 birthdays?
Yes. Day arithmetic is leap-year aware. For a February 29 birth date in a non-leap year, the next birthday falls on March 1, and the year/month/day breakdown reflects the exact calendar gap.
What does "total days lived" mean?
It is the raw number of days between the two dates, counting every leap day in between. It is often larger than years × 365 because of those extra days.
Why might the age differ from a quick "current year minus birth year"?
Subtracting years alone ignores whether the birthday has happened yet this year. This tool checks the month and day, so it does not over-count by a year before the birthday.