Age Calculator
Enter a date of birth to get an exact age and the date of the next birthday.
How it works
Age is counted the way people actually count it: whole years first, then whole months, then the days left over. The calculator walks forward from the date of birth one calendar year at a time until another full year would overshoot the target date, then repeats the process with months and days. That is why the answer is stable — someone born on 31 January is one month old on 28 February, not on 2 March.
Months are not a fixed length, so a month of age means "the same date number in the next month", clamped to the last day where that date does not exist. The totals below the headline figure are plain elapsed counts and will not line up neatly with the years-months-days answer, because a month is not 30 days.
Everything is computed from calendar dates anchored to UTC midnight, so a daylight saving change in your time zone never shifts the result by a day.
Examples
Exact age today. Someone born on 24 March 1994 is, in August 2026, thirty-two years four months and some days old — the figure people actually use, rather than a raw day count.
Age at a past date. Set the second field to a date in the past to answer "how old were they when this happened", which is the common case for records and forms.
A leap-day birthday. Enter 29 February and the anniversary clamps to 28 February in common years, matching how most jurisdictions and most people treat it.
Practical notes
Age is reported the way people count it: completed years, then completed months, then leftover days. That is why someone born on 31 January turns one month old on 28 February rather than on 2 March — the month is complete when the date number is reached or clamped, not after thirty days.
The totals underneath answer a different question and will not reconcile with the headline figure. Total days is an exact elapsed count; total months counts completed calendar months of varying length. Both are right.
For legal purposes, jurisdictions differ on when a person born on 29 February has a birthday in a common year, and on whether age changes at the start of the birthday or at the moment of birth. This calculator clamps to 28 February and treats the whole day as the birthday, which matches ordinary usage rather than any particular statute.
Frequently asked questions
How old am I in days?
The total days figure in the result card is the exact number of days lived, leap days included.
Can I calculate age on a future date?
Yes. Change the second field to any date to see how old someone will be then.
Why does the seconds figure keep moving?
When the target date is today, the seconds total counts up live from midnight at the start of the birth date in your own time zone.
How is someone born on 29 February treated?
Their anniversary falls on 28 February in common years. The calculator clamps to the last valid day of the month, which matches how most jurisdictions treat the date for legal purposes.
Why do the total months and total days not agree?
Because they measure different things. Total days is an exact count of elapsed days; total months counts completed calendar months, which vary between 28 and 31 days. Neither is wrong — they answer different questions.
Can I calculate age at a date in the past?
Yes. Set the second field to any date and the calculator reports the age as of that date rather than today.
Does it count the day of birth?
Age increments on the birthday, so someone born today is zero years old and turns one on the same date next year — the ordinary convention.
Can I calculate the age of something other than a person?
Yes. Any two dates work: the age of a company, a document or a piece of equipment is the same arithmetic.
Why does the next-birthday countdown skip a day some years?
Because a leap day falls between now and then. The number of days to the same date is not constant across years.
Can it show age in weeks?
Yes, along with days, hours and other totals underneath the headline figure.