Fun Facts About Age and Birthdays

This calculator computes your exact age down to the day, tells you what day of the week you were born, and counts down to your next birthday.

How Age Is Calculated

Your age in years increases on your birthday each year. The exact calculation considers the number of full years, remaining full months, and remaining days since your date of birth. Leap years are accounted for automatically.

Day of the Week You Were Born

There is an old nursery rhyme that assigns personality traits to each day: "Monday's child is fair of face, Tuesday's child is full of grace..." While not scientific, it is a fun conversation starter. Mathematically, any date can be mapped to a day of the week using Zeller's formula or the Doomsday algorithm.

Age Milestones Around the World

• 1,000 days old -- about 2 years and 9 months
• 10,000 days old -- about 27 years and 5 months
• 20,000 days old -- about 54 years and 9 months
• 1 billion seconds old -- about 31 years and 8 months

Leap Year Birthdays

If you were born on February 29, you only get a "real" birthday every 4 years. Most leap day babies celebrate on February 28 or March 1 in non-leap years. Legally, different countries handle it differently -- in the UK, a Feb 29 birthday legally falls on March 1 in common years.