Age Calculator
Turn a birth date into an exact age in years, months, and days, with totals and a next-birthday countdown.
Processed locally in your browser — nothing is uploaded.
Age Calculator
Leave empty to use today.
Pick a date of birth to see the age.
About Age Calculator
Pick a date of birth and get the age broken down the way people actually say it — years, months, and days — plus the raw totals in months, weeks, and days. An optional as-of date lets you compute an age at any point in time, past or future.
It also counts down to the next birthday and tells you which weekday it lands on.
Common uses
- Fill in exact-age fields on official forms
- Work out someone's age on a specific historical date
- See how many days until the next birthday and what day of the week it falls on
Example
Input
Born 1990-06-15, as of 2026-08-29
Output
36y 2m 14d · 13,224 days · next birthday in 290 days (Tuesday)
Limitations
- February 29 birthdays roll over to March 1 in non-leap years for the next-birthday countdown.
Frequently asked questions
Does my date of birth leave my device when I use this?
No. The age math runs in your browser with plain JavaScript — your birth date is never sent to a server or stored anywhere, so there's no record of it once you close the page.
How does an age calculator count months when months have different lengths?
It counts whole month anniversaries of the birth date first, then whatever real days are left over. If the anniversary day doesn't exist in a month (born the 31st, say), it clamps to that month's last day — the same convention people use when quoting ages.
Can I work out how old someone was on a specific date?
Yes. Change the as-of date from today to any past or future date and the tool reports the exact age on that day, which is handy for historical records and legal or eligibility cut-offs.
When is your birthday if you were born on February 29?
In non-leap years there is no February 29, so this tool counts the next birthday as March 1 — the day after February 28. Some jurisdictions instead treat February 28 as the legal anniversary, so official rules can differ.