How to use
- Enter your date of birth.
- Leave Age on this date as today, or pick any other date.
- Read your age, the totals and your next birthday.
How age is calculated
- Years: the birthdays you have had.
- Months: whole months since your last birthday. A month completes when its day number comes round again.
- Days: whatever is left over.
The totals count every day between the two dates, including leap days. The calculator uses calendar dates, not clock times, so time zones and daylight saving can’t change the result.
Example
Born 15 January 1990, age on 21 October 2026:
- Last birthday, 15 January 2026: 36 years
- 15 January to 15 October: 9 months
- 15 to 21 October: 6 days
Result: 36 years, 9 months and 6 days, which is 13,428 days.
Leap-day and month-end birthdays
| Rule | 29 Feb birthday in a normal year | Born 31 Jan: 1 month old on |
|---|---|---|
| Next day (default) | 1 March | 1 March |
| Last day of the month | 28 February | 28 February |
The default matches most calculators and spreadsheets. Legal rules differ by country.
Quick facts
| Span | Length |
|---|---|
| Normal year | 365 days (52 weeks + 1 day) |
| Leap year | 366 days (52 weeks + 2 days) |
| Leap years | Every 4 years, except century years not divisible by 400 |
| 1 day | 24 hours = 1,440 minutes |
Planning around a date? See the other Date & Time tools.