Birthday Calculator

Calculate your exact age, days until next birthday, zodiac sign, birthstone, and more. All your birthday calculations in one place.

Enter your date of birth
Calculate age as of this date (default is today)
Calculating...

Understanding Birthday Calculations

A birthday calculator helps you determine your exact age in various units (years, months, weeks, days, hours, minutes, seconds) and provides interesting facts about your birth date such as zodiac sign, birthstone, and historical events.

How Age Calculation Works:

Age is calculated by finding the difference between the birth date and the target date (usually today). The calculation accounts for varying month lengths and leap years to provide an accurate result.

For precise calculations, the time of birth can also be included to calculate age down to the minute or second.

Zodiac Signs & Dates

Sign Symbol Dates Element Planet

Birthstones by Month

Month Birthstone Color Meaning

Interesting Birthday Facts

Most Common Birthday
September 9th in the United States
September birthdays are most common due to conceptions around the holiday season
Least Common Birthday
December 25th (Christmas Day)
Fewer scheduled births on major holidays
Leap Year Birthdays
February 29th
People born on February 29th are called "leaplings" and celebrate on February 28th or March 1st in non-leap years
Golden Birthday
When you turn the age of your birth date
If you were born on the 15th, your golden birthday is when you turn 15 years old

Frequently Asked Questions

Age is calculated by comparing the birth date to the target date, accounting for different month lengths and leap years. The calculation determines the complete years, then remaining months, days, etc., to provide an accurate breakdown.

Western zodiac signs are based on the sun's position relative to constellations and follow a monthly cycle. Chinese zodiac signs follow a 12-year cycle with each year represented by an animal. This calculator shows Western zodiac signs.

If you were born on February 29th (leap day), your birthday in non-leap years is typically celebrated on either February 28th or March 1st. This calculator accounts for leap years and will correctly calculate your age and next birthday.

Birthstones vary by culture and tradition. This calculator uses the modern Western birthstone list, which is the most commonly accepted in English-speaking countries. Some months have multiple birthstones, and we show the primary one.