Age Calculator
Enter your date of birth to see your exact age — and when your next birthday is.
Select your date of birth above
How is age calculated?
Age is calculated as the number of complete years that have passed since the date of birth. A year is only counted once the full calendar year has elapsed — so if your birthday is tomorrow, you are still your current age, not a year older. Months and days are similarly counted as complete calendar months and days remaining after whole years are subtracted.
The "total days lived" figure uses the precise millisecond difference between your birth date and now, divided by the exact number of milliseconds in a day (86,400,000), accounting for leap years automatically.
Frequently Asked Questions
People born on February 29 (leap day) typically celebrate their birthday on either February 28 or March 1 in non-leap years, depending on personal preference and jurisdiction. Legally, in most countries, a person born on Feb 29 turns a given age on March 1 in non-leap years (since Feb 29 doesn't exist, the next day applies). This calculator will show your age correctly — in non-leap years, your birthday is treated as March 1 for the countdown.
In the United States, the most common birthday is September 9, followed closely by other dates in September. This makes sense: September birthdays mean conception around the winter holidays in December. The least common birthdays are December 25 (Christmas Day) and February 29 (leap day). Interestingly, birthdays cluster on mid-week dates, as doctors tend to avoid scheduling elective C-sections and inductions on weekends.
Enter your date of birth above and you'll see your total days lived. As a rough guide: a 10-year-old has lived about 3,650 days; a 30-year-old about 10,950; a 50-year-old about 18,250. These are approximate — the exact number depends on how many leap years fall within your lifetime, which this calculator accounts for precisely.