Age Calculator
Enter your date of birth to see your exact age in years, months and days — plus your age in total months, weeks, days and hours. You can also set an 'as of' date to find how old you were (or will be) on any other day.
How your age is calculated
Your age is the time elapsed between your date of birth and today (or any date you choose). The calculator works out full years first, then the leftover months, then the remaining days, borrowing the correct number of days from the previous calendar month so the result is exact rather than rounded.
Because months have different lengths and leap years add a day every four years, simply dividing the number of days by 365 gives a slightly wrong answer. Counting calendar years, months and days separately is the method used on official forms and is what this tool does.
Why total days and weeks are useful
Seeing your age in total days or weeks is handy for milestones — a 10,000-day birthday, a baby's age in weeks, or counting how long since an anniversary. The 'in total hours' figure is a fun way to appreciate just how much time has passed.
All of these are derived from the same exact day count, so they always agree with the years-months-days result above.
Tips for accurate results
Use the calendar picker to avoid format confusion between day-month-year and month-day-year. Everything runs in your browser, so no information about your birthday is ever sent anywhere.
To find your age on a future date — say, on your next work anniversary — set that date in the optional 'as of date' box.
Frequently asked questions
How do I calculate my exact age?
Subtract your birth date from today's date in whole years, then count the leftover months and days. This calculator does it automatically and also shows your age in total months, weeks, days and hours.
Does the calculator account for leap years?
Yes. It counts real calendar days between the two dates, so the 29 February days in leap years are included automatically.
Can I find my age on a past or future date?
Yes — fill in the optional 'as of date' field with any date and the result updates to your age on that day.