Age Calculator
Enter your date of birth for your exact age in years, months, and days, total days lived, your next birthday countdown, and the day of the week you were born. Instant, private, free forever.
How Age Is Calculated
Age in years is simple subtraction with one correction: current year minus birth year, minus one if this year's birthday has not arrived yet. The months and days are where it gets fiddly, because months are 28 to 31 days long and leap years insert an extra day. The reliable method walks forward from the birthdate: count whole years first, then whole months from the last birthday, then the leftover days. That is exactly what the calculator above does, using your local calendar so leap years and month boundaries land correctly.
Worked example: born June 15, 1990, and today is October 4, 2026. Years: 2026 minus 1990 is 36, and the June birthday already passed, so 36 years. From June 15 to October 15 would be 4 months, but today is October 4, so 3 full months (to September 15) plus 19 days. Result: 36 years, 3 months, 19 days. For the full method, including leap-year edge cases like February 29 birthdays, read our guide to calculating age.
When People Reach for an Age Calculator
Forms are the biggest reason. School enrollment, youth sports leagues, passports, visas, and job applications all ask for age as of a specific date, and getting it wrong by a day can bounce an application. Parents checking school cutoff dates and coaches verifying league eligibility use the "as of" field for exactly this.
Milestone planning is next: how many days until I turn 18, 21, 30, or 65, when retirement or Medicare eligibility kicks in, or when a child ages out of a dependent bracket. Then there is curiosity, the pure kind: what day of the week was I born, how many days have I actually been alive, what percentage of an average lifespan is that. And writers, genealogists, and family historians use it to pin ages to dates in old records, where a headstone gives a birth and death date but no age.
Leap Years and February 29 Birthdays
Leap years do not change your age in years; you still turn a year older on your birthday. They only matter for the day count, adding roughly one extra day every four years. The one genuinely tricky case is a February 29 birthday in a non-leap year: there is no February 29 to walk forward to. Most calculators, including this one, observe the birthday on February 28 in non-leap years, which matches the legal convention in most places. Your year count is unaffected either way.
Frequently Asked Questions
How do I calculate my age?
Subtract your birth year from the current year. If your birthday has not happened yet this year, subtract one more. Then count the full months and remaining days since your last birthday. The calculator above does this automatically, including leap years.
How do I calculate my age in years, months, and days?
First find your full years: current year minus birth year, minus one if this year's birthday has not arrived. Then count complete months since your last birthday, and finally the leftover days. Because months have different lengths and leap years add a day, the safest way is to let a calculator walk forward month by month from your birthdate, which is exactly what the tool above does.
How can I find out what day of the week I was born?
Any date maps to a day of the week on the Gregorian calendar, so a calculator can tell you instantly. Enter your birthdate in the age calculator above and it shows your birth weekday alongside your age.
How many days old am I?
Count the days from your date of birth to today, remembering that leap years add an extra day roughly every four years. The age calculator above shows your total days lived, plus total weeks, months, and hours, automatically.
How do leap years affect age calculation?
Leap years only change the day count, not your age in years. You still turn a year older on your birthday. People born on February 29 legally age on February 28 or March 1 in non-leap years depending on jurisdiction; the calculator above observes February 28.
Is this age calculator free?
Yes, 100% free with no signup. All calculations happen instantly in your browser and your birthdate is never sent to a server. You can even share a link that pre-fills the date.
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Want the full breakdown?
The years-months-days math, leap-year rules, and common mistakes.
Read the Age Guide