How age is calculated
Your age in years is the number of full birthdays you have had. The calculator then counts the full months since your last birthday, and finally the remaining days. For example, someone born on 15 January 2000 is 26 years, 8 months and 27 days old on 12 October 2026.
Because months have different lengths, the month part is counted on the calendar, not as a fixed 30 days. When a birth date does not exist in a month (for example the 31st), the last day of that month is used.
Born on 29 February?
In years without a 29 February, this calculator treats 28 February as your birthday for the countdown. Some people celebrate on 1 March instead; legally, the rule depends on the country.
Uses for an age calculator
- Checking age eligibility for school admission, exams, jobs or government schemes on a specific cut-off date.
- Filling in forms that ask for age in years and months.
- Finding the exact number of days between two dates, for example for a project, a notice period or a pregnancy.
- Planning milestone birthdays such as 10,000 days old.
Frequently asked questions
How do I calculate my exact age?
Count the full years since your birth date, then the full months since your last birthday, then the remaining days. This calculator does it instantly, taking month lengths and leap years into account.
How do I calculate age on a specific date?
Enter your date of birth and change the 'Age on this date' field to the cut-off date. This is useful for exams and admissions that ask for age as on a certain date.
How many days old am I?
Enter your date of birth and the calculator shows your total age in days, weeks, months and hours.
Can I calculate the time between any two dates?
Yes. Use the first date as the start and the second date as the end; the result is the exact difference in years, months and days.