Age Calculator
Enter a date of birth to see your exact age in years, months and days, plus total months, weeks, days and hours lived.
How Old Am I? Calculate Your Exact Age
An age calculator by date of birth tells you exactly how old you are in years, months and days. It is handy for school forms, job applications, insurance quotes, passport paperwork and simple curiosity. Enter your birth date, leave the second date blank to use today or pick another date to see age at that time.
How Age Is Calculated
The calculator subtracts the birth date from the target date. It counts full years first, then remaining months and days, borrowing the correct number of days from the previous month when needed. Total days lived are found from the exact difference between the two dates, and weeks and hours follow from that.
Why Exact Age Matters in the USA
- Driving and voting: many states issue learner permits at 15 or 16, and you can vote at 18.
- Legal age to buy alcohol: 21 nationwide.
- Medicare: eligibility generally starts at 65.
- Social Security: benefits can start as early as 62, and full retirement age is 67 for people born in 1960 or later.
- School enrollment: kindergarten cutoff dates differ by state and district, so check the exact age on a specific date.
Calculate Age on a Specific Date
Use the second date field to find age at any past or future date, for example the age a child will be on the first day of school or the age you will be at retirement. This is also useful for checking eligibility rules that use age on a deadline date.
Leap Years and Birthdays on February 29
People born on February 29 have a birthday only in leap years, but the calculator still counts their age correctly using actual dates. Months have different lengths, so the day count after months may vary from month to month.
Frequently Asked Questions
How many days old am I?
Enter your date of birth and the total days lived appears in the table above.
How do I calculate age from date of birth manually?
Subtract the birth year from the current year, then subtract one if your birthday has not happened yet this year.
Can I calculate someone's age in the past?
Yes. Enter their birth date and set the second date to the day in question.
Calculated using the Gregorian calendar.