Age Calculator
Find an exact age from a date of birth — years, months and days — plus the total days lived, the weekday of birth and a countdown to the next birthday, with the working shown.
Calculate an exact age
An example is worked out below — change the dates and it updates.
The exact age, total days and the working will appear here.
More than a number of years
The exact breakdown, the day count, and what comes next.
Years, months and days
The exact age, broken down the way official forms and people expect it.
Total days
Every day between the two dates counted — often a surprisingly satisfying number.
Next birthday countdown
The date of the next birthday and how many days away it is.
About this age calculator
Your age in years alone is a rounded-down figure — it says nothing about the months and days since your last birthday. This calculator does the full date subtraction: years, then months, then days, borrowing days from the month before and months from the year before exactly the way you would on paper, and shows that working with your dates in it.
That precision matters more often than people expect: school and sports cut-offs, pension and benefits eligibility, insurance, age-restricted purchases and legal documents all turn on an exact age on an exact date, not a rough one. The same calculation also counts the total days between the two dates, finds the weekday of the birth date, and counts down to the next birthday. Dates are handled in UTC inside the calculation, so time zones and daylight-saving changes cannot nudge a result by a day.
Frequently asked questions
How exact ages are worked out, borrows and leap years included.
How is an exact age calculated?
Subtract the birth date from the target date in parts: years first, then months, then days — borrowing days from the previous month (using its real length, leap years included) and months from the previous year when a part goes negative. The steps under your result show the borrows for your dates.
Why does the total-days figure matter?
Some forms, policies and milestones count age in days rather than years — and it is the figure behind celebrations like a 10,000th day. It counts every calendar day between the two dates, leap days included.
Can I calculate an age on a future date?
Yes. Set the second date to any future day — a school start, a retirement date, an 18th or 60th birthday — and the age on that day is shown the same way.
What weekday was I born on?
It is in the results: the weekday of your birth date, worked out from the calendar. It is also a handy cross-check that the date was entered correctly.
What if the birthday has not happened yet this year?
That is handled by the borrowing in the subtraction: the year count drops by one and the months count up from the last birthday, which is why the months figure can be as high as 11.
Are my dates stored anywhere?
No. The calculation runs in your browser; the dates you enter are never uploaded or saved.