Birthday Calculator

A birthday calculator does more than show your age — it pulls together every interesting fact your birthdate generates. Days alive, hours alive, heartbeats (~100,000 per day for an average resting heart rate), the day of the week you were born, your zodiac sign and Chinese zodiac animal, your birthstone and birth flower, what number birthday you're heading toward, and how many days until your next one. This calculator does the math accurately — accounting for leap years (every 4th year, except century years not divisible by 400, which is why 1900 wasn't a leap year but 2000 was), variable month lengths, and time zone differences — and presents the results in a clean, shareable format. The cultural traditions associated with birthdays vary widely: in Korea, ages traditionally jumped on Lunar New Year regardless of actual birthday until the country switched to international age reckoning in 2023. In Vietnamese tradition, you're considered 1 year old at birth. The Gregorian calendar we use today wasn't adopted in Britain and its American colonies until 1752 — which is why George Washington celebrated his birthday on both Feb 11 (old style) and Feb 22 (new style). This tool sticks to the modern Gregorian calendar and gives you a complete birthday snapshot for any date.