How to use the age calculator
You only need one date: the date of birth. The second date starts on today, so the result answers "how old am I right now?" Change it to any other day to see how old someone was at a past event or will be on a future one.
If the birth date is February 29, a third option appears. Pick whether the birthday falls on February 28 or March 1 in years without a leap day.
- Enter the date of birth.
- Keep today's date or pick the day you want the age for.
- For a February 29 birthday, choose February 28 or March 1 for common years.
- Press Calculate exact age.
- Read your age at the top, then the totals, birthdays and milestones below it.
Age example: born January 15, 1995
Here's what the result looks like for a January 15, 1995 birth measured on August 10, 2026. The last birthday was January 15, 2026, so 31 full years have passed. Six full months take you to July 15, and 26 days are left over.
The same person was born on a Sunday, has lived 378 full months, and turns 32 on Friday, January 15, 2027.
| Result | Value |
|---|---|
| Exact age | 31 years, 6 months, 26 days |
| Total days lived | 11,530 |
| Total weeks | 1,647 weeks and 1 day |
| Full months lived | 378 |
| Day of the week born | Sunday |
| Days until next birthday | 158 |
| Approximate decimal age | 31.5681 years |
How old am I? The birthday check
Most mistakes come from subtracting years and stopping there. 2026 minus 1990 is 36, but someone born October 20, 1990 is still 35 on August 10, 2026. Their birthday is 71 days away.
So the rule is simple. Subtract the birth year from this year. If your birthday hasn't come yet this year, take off one. That gives your age in whole years, the number most forms ask for.
Age in years = current year - birth year - (1 if this year's birthday hasn't happened yet, otherwise 0)Exact age = full years since birth + full months since the last birthday + days left overTotal days lived = date counted to - date of birth, in calendar days
Chronological age in years, months and days
Chronological age is just time since birth on the calendar, as opposed to a developmental, reading or biological age. Schools, speech therapists and psychologists often write it as years and months, like 7;4, on test forms.
The United Nations separates two ideas. Exact age is the full time since birth. Completed age, or age at last birthday, is the whole number of years. This page shows both: the years, months and days at the top and completed years in the details.
If a test manual or school form spells out its own way of counting months and days, follow the manual. The calendar method here counts real months, so a 28-day February and a 31-day March are each one month.
February 29 birthdays
Someone born on February 29 only gets their real birthday once every four years. In other years you need a stand-in date, and February 28 and March 1 are both used.
The choice changes the answer near the birthday. For a February 29, 2000 birth measured on February 28, 2001, the February 28 rule gives 1 year, 0 months and 0 days. The March 1 rule gives 0 years, 11 months and 30 days. The calculator uses your choice for the age, the birthdays and the milestones.
What each result means
Hours and minutes are total days times 24 or 1,440. The form doesn't ask for a birth time, so treat them as a sense of scale, not a stopwatch reading.
| Result | What it means | Precision |
|---|---|---|
| Years, months, days | Full years, then full months, then leftover days | Exact for the dates entered |
| Completed years | Birthdays already reached | Exact |
| Total days and weeks | Calendar days between the two dates | Exact |
| Hours and minutes | Total days x 24 or x 1,440 | Date-level only |
| Decimal age | Total days / 365.2425 | Approximate |
When your official age follows a different rule
The math here is ordinary calendar arithmetic. Some programs count age differently. U.S. Social Security, for example, treats you as reaching an age on the day before your birthday. Schools and sports leagues use age on a fixed cutoff date.
Use the result to check the dates, then read the rule of whoever is asking. If you only know a birth year, or the date came from a record in another time zone, the calculator can't fill in what's missing.
Sources
These references back the age definitions, leap-year rule and age-attainment examples on this page.