Age Calculator
This age calculator tells you exactly how old you are in years, months, and days, starting from your date of birth up to today (or any date you choose). It also breaks your age down into total months, weeks, days, and hours, and counts down the days until your next birthday. It is useful for filling out forms, checking eligibility requirements, or simply out of curiosity.
Your age
In months
In weeks
In days
In hours
Next birthday
Age is calculated using the Gregorian calendar, accounting for leap years. The totals in months and weeks are rounded down.
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How it works
The calculator subtracts your date of birth from the target date using the Gregorian calendar. It first works out the difference in years, then months, then days, "borrowing" from the previous unit whenever the day or month of the target date is smaller than that of your birth date — the same way you subtract by hand. Leap years are handled automatically, so a person born on February 29 ages correctly. The total in days is the raw number of calendar days between both dates; months and weeks are derived from that and rounded down to the nearest whole unit.
Years completed versus exact age
In everyday use, age is given in completed years: the number of times your birthday has already passed. Exact age goes further and adds the months and days since your last birthday, so someone can be "30 years old" and, precisely, 30 years, 4 months and 12 days. A special case is people born on 29 February: because that date only exists in leap years, in common years they usually mark their birthday on 28 February or 1 March, though legally they still age every year.
One age expressed in different units
The same age can be written in years, months, weeks, days or hours. Because months and years have different lengths, the equivalences below are approximate (a year of 365.25 days is used to average out leap years). They give you a sense of the order of magnitude, not an exact figure: for that, use the calculator's real-date calculation.
| Age | Months | Days (approx.) | Hours (approx.) |
|---|---|---|---|
| 10 years | 120 | 3,653 | 87,660 |
| 18 years | 216 | 6,575 | 157,788 |
| 30 years | 360 | 10,958 | 262,980 |
| 50 years | 600 | 18,263 | 438,300 |
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Preguntas frecuentes
- How is my exact age calculated?
- Your age is the difference between your date of birth and the target date, expressed in complete years, then the remaining complete months, then the remaining days. For example, someone born on 15 March 2000 is, on 20 June 2024, 24 years, 3 months, and 5 days old. Leap years and the different lengths of each month are taken into account.
- Does the calculator account for leap years?
- Yes. The calculation is based on real calendar dates, so leap years (with February 29) are handled automatically. A person born on 29 February will see their age increase correctly every year, and the total number of days always reflects the actual days elapsed.
- Can I calculate my age at a future or past date?
- Yes. By default the calculator uses today, but you can change the "calculate age as of" date to any date. This lets you check how old you were on a specific past event, or how old you will be at a future date such as a graduation or retirement.
- Why is my age in months not simply my years times twelve?
- The "in months" total counts every complete month between the two dates, not just full years multiplied by twelve. Because months have different lengths, this is the most accurate whole-month count. It is derived from the exact year-month-day breakdown and rounded down to the last complete month.
- How is the countdown to my next birthday worked out?
- The calculator finds the next occurrence of your birth month and day on or after the target date, then counts the calendar days until then. If your birthday falls on 29 February and the upcoming year is not a leap year, most calendars treat it as 1 March for the countdown.