Age Calculator

Example Calculation

Someone born on June 15, 1990 is, on October 11, 2026, 36 years, 3 months and 26 days old. That is 435 months, or 13,267 days, and 1,895 full weeks.

Their next birthday, June 15, 2027, is 247 days away. The calculator also works for past or future dates, so you can check an age on any day, such as a school cutoff date.

How It Works

Your age is more than a single number. This age calculator takes your date of birth and a comparison date — today by default — and reports your exact age as years, months and days, along with totals in months, weeks, days and hours. You can change the “age at” date to find out how old you were or will be on any day, which is useful for eligibility checks, school cutoffs and milestone planning.

To calculate the breakdown, the tool subtracts the birth date from the target date field by field. When the day of the month is smaller than the birth day, it borrows days from the previous month; when the month is smaller, it borrows a year. This calendar-aware method matches how age is commonly counted, rather than dividing days by 365, which would drift because of leap years.

Total days are found by measuring the exact difference between the two dates, then converted to weeks and hours. The next-birthday line shows how many days remain until your next birthday and which weekday it falls on, which is a fun way to plan celebrations.

Common uses include verifying minimum-age requirements for jobs, driver’s licenses, retirement benefits and sports leagues; calculating a child’s age in months for developmental milestones; and finding out how long you have been alive for fun. For legal or official purposes, always rely on documents such as a birth certificate and the rules set by the relevant organization, as some use different cutoff dates or counting conventions. People born on February 29 are counted using their calendar birthday in leap years, and commonly celebrate on February 28 or March 1 in other years.

Formula Explained

Years = difference in calendar years, adjusted down by one if the birthday has not yet occurred this year. Months and days are found by borrowing from the previous month when needed.

Total days = (target date − birth date) ÷ 86,400,000 ms; hours = days × 24.

Assumptions and limits

• It uses the Gregorian calendar, including leap years. A February 29 birthday is treated as March 1 in years that are not leap years.
• Dates are compared as calendar days, without times or time zones.
• The result is for personal use. For legal, school or benefit purposes, rely on official documents and the rules of the organization.