How to use
- Pick a date of birth.
- “Age on” is today by default. Change it to see the age on any other date, for example an application deadline.
- You get:
- Age: whole years, plus the exact age in years, months and days.
- Next birthday: how many days are left, the date and the age it brings. On the day itself it says “Today!”.
- Days lived, and the same span in weeks and in months.
- The day of the week you were born.
How it is calculated
The calculator steps forward from the date of birth one month at a time until the next step would pass the “Age on” date. Every 12 months is a year, and the days left over are the days. When a month is shorter than the birth date, it uses the last day of that month, so January 31 plus one month is February 28 (or 29).
Total days lived = “Age on” date − date of birth. Leap days are included because the count uses real calendar dates.
Example
Someone born on Sunday, May 20, 1990, on October 11, 2026:
| Result | |
|---|---|
| Age | 36 years, 4 months, 21 days |
| Days lived | 13,293 days |
| In weeks | 1,899 weeks exactly |
| In months | 436 months |
| Next birthday | In 221 days (May 20, 2027, turning 37) |
Someone born on February 29, 2004 is 22 years, 7 months and 12 days old on October 11, 2026. Their next birthday in this calculator is February 28, 2027, because 2027 is not a leap year.
Common uses
- Baby milestones: doctors and parents often track age in months and days in the first two years.
- Eligibility checks: sports leagues, school entry, exams and insurance often set an age on a cutoff date.
- Birthday countdowns: see how many days are left and which day of the week it falls on with the date calculator.