How this age calculator works
Your age is the amount of time that has passed since you were born. The most common way to express it is in completed years — the number of times your birthday has come around. This calculator goes further and breaks the gap between your date of birth and a chosen date into whole years, months and days.
To stay calendar-accurate, it counts complete years first, then the remaining complete months, then the leftover days. If the day-of-month on the target date is earlier than your birth day, the last month is not yet complete, so the tool borrows days from the previous calendar month — which is why a result can read, say, "35 years, 11 months, 28 days" rather than a rounded figure.
Reference note: calculations use the Gregorian calendar and your device's local date. Leap years are handled automatically, so a 29 February birthday counts its anniversary on 28 February / 1 March in common years depending on your browser's date handling.
Frequently asked questions
- How is age calculated?
- Your age is the number of complete years between your date of birth and the chosen date. We count whole years, then the remaining whole months, then the leftover days, borrowing days from the previous month when needed.
- How many days have I been alive?
- It is the number of whole days between your date of birth and today. The calculator shows that total along with the equivalent weeks and hours.
- What day of the week was I born on?
- Enter your date of birth and the tool shows the weekday it fell on — for example Monday or Saturday — using the Gregorian calendar.
- How do I calculate age from a birth date?
- Subtract the birth date from the current date: count complete years, then complete months, then remaining days. If today's day-of-month is earlier than your birth day, subtract one and borrow the days.
- How many days until my next birthday?
- It is the number of days from today until your birth month and day come around again. The calculator also shows the age you will turn.
- Why might my age differ by a day across time zones?
- Dates follow the local clock. If it is already tomorrow somewhere but still today elsewhere, a day count or birthday can shift by one. This tool uses your device's local date.