Age Calculator

Pick the date from the calendar, or type it as MM/DD/YYYY.

Leave blank to use today. Set a past or future date to see an age on that day.

How old am I, exactly?

Your age is the time that has passed since the day you were born — but the number most people want is not just “36” or “27”. Forms, schools, and doctors often ask for your age in years, months, and days, and that breakdown is where hand math goes wrong, because months are not all the same length and every fourth year adds a leap day.

This calculator does the calendar math for you. Enter your date of birth and it shows your exact age in years, months, and days, your total days lived, your total months and weeks, the weekday you were born on, and how many days are left until your next birthday. Leave the second date blank to calculate as of today, or set it to any past or future date — for example, to find out how old you will be on the first day of a new job, or how old you were on the day of an old photo.

Everything runs in your browser. Your birth date is never sent to a server, stored, or shared.

Worked example

Say you were born on June 15, 1990, and today is October 25, 2026. Subtracting years alone gives 2026 − 1990 = 36, and this time that part happens to be right — your birthday in June has already passed this year. Counting forward from your last birthday, June 15, 2026, to October 25, 2026 adds 4 full months (to October 15) and 10 more days. So you are 36 years, 4 months, and 10 days old, and you have lived 13,281 days. Your next birthday is June 15, 2027 — 233 days away — when you turn 37.

Try it yourself: enter June 15, 1990 above, set “calculate age on” to October 25, 2026, and check that you get the same result.

How the calculation works

The calculator counts completed years first, then completed months, then the remaining days — the same order birthdays actually fall in.

  1. Years: your age in full years is the number of birthdays you have already had. If your birthday has not happened yet this year, you are still last year’s age.
  2. Months: from your last birthday, count full months forward. A month completes on the same day-of-month it started on — February 20 to March 20 is one month.
  3. Days: whatever is left after those full months is the days figure.

Leap years are handled automatically, because the math walks the real calendar instead of dividing by 365. That matters: 15 years is not always 5,475 days — it is 5,479 days if it spans four leap days, and 5,478 if it spans three.

Leap-day birthdays: if you were born on February 29, your birthday falls on March 1 in non-leap years in this calculator. So someone born February 29, 2000, is 24 years, 11 months, and 30 days old on February 28, 2025, and turns 25 the next day, March 1, 2025. (Some places treat February 28 as the birthday instead; for legal paperwork, follow your local rule.)

End-of-month dates: a month only completes when its day-of-month arrives. February 28 to March 31 is 1 month and 3 days, and March 31 to April 30 is 30 days — April has no 31st, so that month never completes.

Common mistakes

  • Subtracting only the years. Born December 31, 1990? In October 2026 you are still 35, not 36 — your 36th birthday has not happened yet. Year subtraction is off by one for everyone whose birthday is still to come this year.
  • Dividing days by 365. That gives a rough age, not a calendar age, because it ignores leap days and treats every month as equal. It is fine for a guess and wrong for a form.
  • Counting the current month as complete. If your last birthday was June 15 and today is October 10, you are 3 months and 25 days past it — not 4 months. The fourth month completes on October 15.
  • Forgetting February 29. Someone born on a leap day has still aged a full year by the time their non-leap-year birthday date arrives, even though February 29 is not on that year’s calendar.

When an exact age matters

  • School enrollment: kindergarten and preschool cutoffs turn on whether a child has reached the required age by a specific date.
  • Age limits: driving, voting, drinking, and rental-car rules all check whether a birthday has actually passed, not just the birth year.
  • Forms and applications: many official forms ask for age in years, months, and days — the exact breakdown this calculator gives.
  • Medical and growth records: pediatric notes often record a child’s age in total weeks or months rather than years.
  • Milestones: your 10,000th day alive, your next birthday countdown, or how old you will be on a future date you are planning around.

Frequently asked questions

How do I calculate my age from my date of birth?

Count the birthdays you have already had for the years, then full months since your last birthday, then the remaining days. Or enter your birth date above — the calculator does all three steps, including leap years, in one go.

How many days old am I?

That depends on your exact birth date, not just your age in years, because of leap days. Enter your birth date above and read the “Total days lived” figure — for example, someone born June 15, 1990, had lived 13,281 days by October 25, 2026.

Why does simple year subtraction sometimes give the wrong age?

Because it ignores whether your birthday has happened yet this year. If you were born in 1990 and your birthday is in December, you are still 35 for most of 2026 even though 2026 − 1990 = 36. You turn 36 on your birthday, not on New Year’s Day.

How old will I be on a future date?

Set the “Calculate age on this date” field to that date. For example, someone born March 10, 1985, will be 44 years, 9 months, and 22 days old on January 1, 2030.

What happens if I was born on February 29?

You still age one year per year. In this calculator your birthday is counted on March 1 in non-leap years, so you turn a year older on March 1. Some jurisdictions use February 28 instead — for legal documents, check your local rule.

Is my birth date stored or shared?

No. The calculation happens entirely in your browser. Nothing is sent to a server, no account is needed, and nothing is saved after you leave the page.

Disclaimer

This calculator gives informational results based on the standard calendar-age system used in most of the United States, where age increases on your birthday. It is not legal, medical, or official advice. For passports, benefits, school enrollment, or any legal age determination, confirm the result with the issuing authority — especially for February 29 birthdays, where local rules differ.

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