Enter your date of birth in the calculator above and it will instantly show the exact number of days, months, weeks, and hours until your next birthday. If your birthday is today, a special banner will appear!

The birthday calculator shows the exact day of the week you were born — Monday, Tuesday, Wednesday, etc. — based on your birth date. People born on Sunday are sometimes called "Sunday's child" (from the old nursery rhyme "full of grace"), while Monday's child is "fair of face".

In numerology, your Life Path Number is calculated by summing all the digits of your full birth date (day + month + year) and reducing to a single digit (1–9) or master number (11, 22, 33). It's said to reveal your life purpose and personality traits. For example, a Life Path 1 person is a natural leader, while a Life Path 7 is analytical and introspective.

Subtract your birth date from today's date to get the number of days you've been alive. The calculator does this automatically and also shows your age in months, weeks, hours, and even seconds. For example, a 30-year-old has lived approximately 10,957 days (accounting for leap years).

Generations are defined by birth year ranges: Silent Generation (1928–1945), Baby Boomers (1946–1964), Generation X (1965–1980), Millennials / Gen Y (1981–1996), Generation Z (1997–2012), and Generation Alpha (2013–present). The calculator shows your generation based on your birth year.

The birthday paradox (or birthday problem) states that in a group of just 23 people, there is a 50.7% probability that at least two people share the same birthday. With 57 people, the probability exceeds 99%. This seems counterintuitive because we naturally think of our own birthday and compare it against 22 others — but the paradox compares every pair of people against each other, which is 253 possible pairs in a group of 23.