Exact age, days lived, and countdown to next birthday
A tool that works out exactly how old someone is, or was, or will be, on any given date — not just in years, but broken down into years, months, days, and even total hours and seconds lived.
Enter a date of birth.
Set "Calculate as of" — defaults to today.
Read the exact age and stats below, updated instantly.
By counting full years first, then full months, then whatever days are left over — and correctly borrowing across shorter months (like a 28- or 29-day February) so the day count never goes negative. It's real calendar math, not just a rough days-divided-by-365 estimate.
Enter a date of birth and the calculator compares it against your chosen "as of" date to produce the full breakdown — years, months, days, and every total stat below it.
Born January 31, calculating as of March 1 the following year: that's 1 year, 1 month, and 1 day — not a flat 397-day estimate. The calculator borrows from February's actual length that year rather than assuming every month has 30 days, which is exactly what makes edge cases like a January 31 birthday come out correct.
The large headline number is this exact breakdown — not a rounded age, but the real years, months, and days between your date of birth and the date you're calculating as of.
Leave "Calculate as of" on its default value and it's set to today automatically, so entering just your date of birth is enough to see your current exact age.
Change "Calculate as of" to any past or future date to see how old you were, or will be, at that point — useful for figuring out your age on an exam date, a travel date, or an anniversary.
The Total Days Lived stat shows the exact day count between your date of birth and the "as of" date, alongside total weeks, hours, minutes, and seconds for the same span.
Total Weeks is shown as its own stat. Total months isn't shown as a separate running count — instead, the exact number of months is the middle figure in the years/months/days headline above, which is the more precise way to express it since a flat "months old" number would have to round.
Chronological age just means age counted by the calendar — years, months, and days since birth — as opposed to things like biological or "feels like" age. That's exactly what this tool computes: a real calendar-based age, not an estimate.
There's no separate two-person screen, but the same two fields do the job: put one person's date of birth in "Date of birth" and the other person's date of birth in "Calculate as of," and the result is the exact age gap between them in years, months, and days.
The Days To Next Birthday stat counts forward from your "as of" date to your next birthday automatically, and switches to "Today!" on the day itself.
Get an exact age for a date that isn't today, without doing the calendar math by hand.
See exactly how many days you've been alive, or how many days until your next birthday.
Work out the exact age gap between two people, down to the day.
By counting full years, then full months, then remaining days between your date of birth and the date you're calculating as of, borrowing correctly across shorter months (like February) so the day count never goes negative.
Yes. The "Calculate as of" field defaults to today but can be set to any date, so you can see how old you were on a past date or will be on a future one.
Yes, using the same two fields: enter one person's date of birth as the birth date and the other person's date of birth as the "calculate as of" date, and the result shows exactly how far apart in years, months, and days they are.
The Total Days Lived stat shows this directly, along with total weeks, hours, minutes, and seconds for the same span.
The Days To Next Birthday stat counts down to it automatically, based on your date of birth and the date you're calculating as of.
Yes. The month/day math accounts for actual month lengths, including February in leap years, so the years/months/days breakdown stays correct regardless of which months fall in between.