Age Calculator
Exact age plus birthday countdown · Page last updated August 2026
Defaults to today if left blank
Results
Age
Total Days Lived
Total Weeks
Next Birthday In
How the Age Calculator Works
Enter a date of birth and, optionally, a date to calculate age as of - it defaults to today. The calculator counts full calendar years, then full months, then remaining days, the same way you'd count by hand on a calendar. It also totals the number of days and weeks lived, and counts down to the next birthday from your chosen date.
Everything runs locally in your browser - your date of birth is never sent anywhere.
Frequently Asked Questions
How is the years/months/days age calculated?
It counts full calendar years, then full calendar months, then remaining days between your date of birth and the "as of" date - the same way you'd count on a calendar, not just by dividing total days.
Can I calculate age as of a date other than today?
Yes - the "Calculate age as of" field defaults to today but can be set to any date, useful for figuring out age at a past or future event.
Does this store my date of birth anywhere?
No - the calculation happens entirely in your browser and nothing is sent to a server. If you calculate and the link becomes shareable, the date is only encoded in that URL, not stored by us.