Your exact age, down to the day
Enter a date of birth and the date to count to, today unless you change it, for the age in years, months and days, the totals in weeks, days and hours, the weekday of birth and the next birthday. Both dates stay in your browser and are never sent anywhere.
The next ten birthdays
The weekday each one falls on and how far away it is, counted from the date above.
| Birthday | Turning | Days away |
|---|
Questions
Built by Mohd Shayan. Found a problem or have an idea? Send a note.
How is the age in years, months and days worked out?
Whole years are counted first, then whole months, then the days left over, by stepping the birthday forward through the real calendar. Someone born on 14 March 1990 is 36 years, 6 months and 28 days old on 12 October 2026: 36 years reach 14 March 2026, 6 more months reach 14 September 2026, and 28 days remain. There is no 365.25-day year or 30-day month anywhere in the maths; every month has its true length and each leap day counts as a day.
What if I was born on 29 February?
In a leap year the birthday is 29 February. In a common year the calculator treats 28 February as the birthday, so a year of age is added on the last day of February rather than on 1 March. Someone born on 29 February 2000 turns 26 on Saturday 28 February 2026, has their next birthday on Sunday 28 February 2027, and is back on 29 February in 2028, a Tuesday. Some legal systems use 1 March in a common year instead; this calculator uses 28 February throughout.
Why does a birthday near the end of a month give an odd count?
When the day of birth does not exist in a later month, that month is counted on its last day. Someone born on 31 January is 1 month old on 28 February in a common year (29 February in a leap year) and 1 month and 1 day old on 1 March. The total in days is unaffected: 31 January 2025 to 1 March 2025 is 29 days, or 4 weeks and 1 day, however the months are counted.
How are the totals in months, weeks, days and hours calculated?
Total days is the exact number of calendar days between the two dates, leap days included, taken from the calendar rather than from an average year. Weeks are that figure divided by 7 with the remainder shown in days, and hours are the days times 24: the calculator works with dates, not times of birth, so both days are taken to start at midnight. 14 March 1990 to 12 October 2026 is 13,361 days, which is 1,908 weeks and 5 days, or 320,664 hours. Total months is the whole months counted the same way as the age, with the leftover days beside it.
Is anything I enter saved or sent anywhere?
No. The dates are read by JavaScript in your browser, and the page makes no network request with them. Today comes from your device's clock and time zone. If you press Copy link, both dates are written after the # in the page address, which browsers never send to a server, so you can bookmark the result or send it to someone.
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