Age Calculator by Date of Birth
Use this free age calculator by date of birth to calculate exact age in years, months, days, total weeks, total days, and next birthday.
Age Calculator
Use this for forms, school admission dates, birthdays, work records, family history notes, and finding age on a past or future date.
Calculate Exact Age From Date of Birth
An age calculator by date of birth finds the time between a birthday and another date. Use it to answer how old am I today, calculate age on a future date, calculate age on a past date, find total days lived, total weeks, and days until the next birthday.
This calculator uses calendar dates, so month lengths and leap years are handled automatically. For leap day birthdays, the next birthday falls on the closest valid date in non-leap years.
Age Calculator FAQs
How does the age calculator work?
Enter a date of birth and an optional end date. The calculator counts the calendar difference in years, months, and days, then also shows total days and weeks.
How old am I if I enter my date of birth?
Enter your date of birth and leave the age-on date set to today. The calculator shows your exact age in years, months, and days, plus total days and weeks.
Can I calculate age on a future date?
Yes. Change the end date to any future date to calculate how old someone will be on that day.
Can I calculate age on a specific past date?
Yes. Enter the date of birth and set the age-on date to the past date you want to check, as long as it is on or after the birth date.
Does the calculator handle leap years?
Yes. The age calculator uses real calendar dates, so month lengths and leap years are included in the result.