Why people use age calculators calculators
Age comes up on forms, in eligibility checks, for insurance and pensions, in medical dosing, and for the simple curiosity of knowing how many seconds you have been alive. Converting a birth date into an exact age in an unusual unit is fiddly by hand because years vary in length and the answer changes continuously.
How these calculators work
Enter your date of birth and the calculator subtracts it from the present moment, converting the elapsed interval into the unit shown on this page. The breakdown beneath the result restates the same age in years, days, hours and seconds so you can copy whichever figure you need.
Whole years are counted the way people and legal systems count them: your age increases on your birthday, not on a rolling 365-day cycle. Leap days are included in the day and second totals, which is why the two figures do not divide evenly into each other.
Tips
- Nothing you type leaves your browser — the birth date is never sent anywhere.
- For someone else's age, enter their birth date instead; the calculator does not assume the date belongs to you.
- Pair this with the birthday countdown calculators below to see how long until the next milestone.