Age Calculator
Enter a date of birth to see your exact age in years, months and days, plus the total months, weeks and days lived.
Last updated October 19, 2026
Defaults to today
Result
36 years, 4 months, 28 days
436 months · 1,899 weeks · 13,299 days · Born on a Friday
Show the work
- Whole years from June 15, 1990 to November 12, 2026: 36 years.
- Whole months after the last birthday: 4 months.
- Remaining days: 28 days.
- Totals: 436 months, 1,899 weeks, 13,299 days.
How age is calculated
age = end date − date of birth, counted as whole years, then whole months, then the remaining days
The calculator counts complete calendar years from the date of birth, then complete months, and finally the days left over. A birthday counts on the day itself: someone born on June 15 is one year older on June 15.
A month counts as complete only when the day of the month of the end date has reached the birth day of the month. The complete months are then added to the birth date, with the day cut back to the last valid day (January 31 plus one month is February 28), and the days from that date to the end date make up the day count. Someone born on January 30 is therefore 0 months and 29 days old on February 28, 2026, not 1 month. A February 29 birthday is counted as passed on March 1 in years that are not leap years.
See how we calculate for the formulas, sources and review schedule behind every calculator.
Also useful alongside this calculator: Birthday Calculator.
Age in years, months, weeks and days
The same age can be written in several units, and each one answers a different question. Years, months and days is the form used on forms and in everyday conversation. Total months suits growth charts and schedules that run in months. Total weeks is common in pregnancy and early infancy, and total days is used for exact intervals.
In the worked example the age is 36 years, 4 months and 4 days. That is 36 × 12 + 4 = 436 complete months, 1,896 complete weeks and 13,275 days. The weeks figure rounds down: 13,275 ÷ 7 = 1,896 weeks and 3 days.
Why age is not simply days ÷ 365
Dividing the days lived by 365 is only an approximation, because years are 365 or 366 days long and months range from 28 to 31. For the 13,275 days above, 13,275 ÷ 365 gives 36.37, while 13,275 ÷ 365.25 gives 36.34. Neither tells you how many whole years have passed or which month you are in.
The calendar method avoids that. It counts whole years first, which is why a person is still 35 on the day before the 36th birthday however many days they have lived. Month ends are handled the same way: someone born on January 31, 2000 who checks on March 1, 2026 is 26 years, 1 month and 1 day old, because one month after January 31 is the last day of February.
Checking age on another date
Changing the "Age at the date of" field answers questions such as how old a child will be on the first day of school, whether someone meets a minimum age on an event date, or how old a person was on a past date. A child born on September 1, 2020 is exactly 6 years, 0 months and 0 days old on September 1, 2026.
A February 29 birthday shows the effect of leap years: someone born on February 29, 2004 is 21 years, 11 months and 30 days old on February 28, 2026, and 22 years, 0 months and 1 day old on March 1, 2026. They turn 24 on February 29, 2028. This calculator uses the international system, in which a person is zero years old at birth, rather than traditions that count a newborn as one.
How to use the Age Calculator
- Enter the date of birth.
- Keep "Age at the date of" set to today, or pick another date to see the age on that day.
- Read the result in years, months and days, and open "Show the work" to see the totals.
- Use Copy, Print or Share to keep or send the result.
Worked example
Someone born on June 15, 1990 checks their age on October 19, 2026. The 36th birthday was June 15, 2026, so the complete years are 36. The complete months after that birthday are 4 (up to October 15, 2026), and the remaining days are 4. The age is 36 years, 4 months and 4 days, which is 436 months or 13,275 days in total.
| Age | Date reached | Weekday |
|---|---|---|
| 18 | June 15, 2008 | Sunday |
| 21 | June 15, 2011 | Wednesday |
| 30 | June 15, 2020 | Monday |
| 40 | June 15, 2030 | Saturday |
| 50 | June 15, 2040 | Friday |
| 65 | June 15, 2055 | Tuesday |
Frequently asked questions
How do you calculate exact age?
Count the complete years since the birth date, then the complete months after the last birthday, then the remaining days. The worked example above shows each step.
Does the calculator count the day of birth?
The birth date is day zero. Age goes up by one year on each birthday, and the total-days figure counts the days elapsed after the birth date.
How is a February 29 birthday handled?
In years that are not leap years the birthday counts as passed on March 1. For someone born on February 29, 2004, February 28, 2026 shows 21 years, 11 months and 30 days, and March 1, 2026 shows 22 years, 0 months and 1 day. On February 29, 2028 they are exactly 24.
Are my dates stored or sent anywhere?
No. The calculation runs in your browser and nothing you enter is saved or uploaded.