Defaults to today.
How to use the Age Calculator
- 1Select your date of birth.
- 2Leave Age at the date of set to today, or choose another date to find your age on that day.
- 3Read your age in years, months and days.
- 4Check the totals for months, weeks and days lived, and the countdown to your next birthday with the weekday it falls on.
How age is calculated
Age is counted the way people normally state it: first the number of complete years since your birth date, then the complete months since your last birthday, then the remaining days. If the day of the month in the target date is earlier than your birth day, a month is borrowed and the days are counted from the corresponding day in the previous month, so the result always reflects actual calendar months rather than an average month length.
The totals are calculated separately. Total days lived is the exact number of calendar days between the two dates, total weeks is that figure divided by seven and rounded down, and total months is the number of complete months that have passed. Our guide on how to count the days between two dates explains the counting rules in more detail.
Leap years and February 29 birthdays
A leap year has 366 days, with February 29 added. Leap years occur every four years, except for century years that are not divisible by 400. So 2000 was a leap year, but 1900 was not. Because the calculator uses real calendar dates, leap days are included automatically in the total days lived.
If you were born on February 29, this calculator treats February 28 as your birthday in non-leap years. That means you turn a year older on February 28 in those years, and the next birthday countdown points to February 28 or February 29 depending on whether the coming year is a leap year. Legal rules for leap-day birthdays vary by country, and some use March 1 instead.
Common uses for an age calculator
Exact age is often needed for forms and applications, such as checking eligibility for school admission, sports age groups, retirement plans, insurance or government programs that use a cut-off date. Set the Age at the date of field to the cut-off date to see your age on that day.
It is also useful for milestones: finding the date you turn 10,000 days old, working out a child’s age in months for health checks, or calculating the time between any two dates, such as how long ago an event happened, which the date difference calculator also handles.
Learn more
Frequently asked questions
How do I calculate my age in days?
Enter your date of birth and the calculator shows the total number of days you have lived up to today, or up to any date you choose. The count uses real calendar dates, so leap days are included.
Can I find my age on a specific past or future date?
Yes. Change the Age at the date of field to any date. This is useful for eligibility cut-offs, such as being a certain age on the first day of a school year. To count down to any other event, use the days until calculator.
How are February 29 birthdays handled?
In years without a February 29, the calculator counts your birthday on February 28. In leap years it uses February 29 as normal.
Why might my age in months seem off by one?
Only complete months are counted. If your birthday day of the month has not yet arrived in the current month, that month is not counted yet, and the remainder appears in the days figure instead.
Is my date of birth stored?
No. The calculation runs entirely in your browser and your date of birth is never uploaded or saved. More date tools are in the date and time calculators section.