Age Calculator
Calculate exact age, compare 2 birth dates, check the next birthday, or prepare chronological age for an assessment date.
Full Age Calculation GuideEnter calendar dates only. Your dates stay in this browser and are not saved.
Counts completed calendar years, months and days.
Advanced options (optional)Choose how a February 29 birthday is handled in a non-leap year.
Everyday and legal conventions differ. Select the rule appropriate to your purpose.
Transparent methodology
How the age calculation works
1. Choose the purpose
Calculate an exact age, compare 2 dates, or prepare an assessment-age result.
2. Enter calendar dates
Dates are handled without a time zone so daylight-saving changes cannot shift the result.
3. Count complete units
Everyday age counts complete years, complete months and the remaining days.
4. Review the convention
Leap-day and assessment conventions remain visible instead of being applied silently.
Worked example
Someone born September 10, 2000 is 25 years, 11 months and 30 days old on September 9, 2026. On the next day—their birthday—the completed age becomes 26 years, 0 months and 0 days.
Calendar rules
Everyday age and assessment age can follow different conventions
For everyday age, the calculator advances through actual calendar anniversaries. This respects different month lengths and Gregorian leap years.
Some standardized assessment manuals instead instruct examiners to borrow exactly 30 days when the test-day number is earlier than the birth-day number. Assessment Age mode keeps that convention separate and labels it clearly. Always follow the instructions supplied with the assessment you are using.
Answers before you calculate
Frequently asked questions
How is exact age calculated?
Exact age counts completed calendar years first, then completed months, then the remaining days. It uses actual calendar dates rather than treating every year as 365 days or every month as 30 days.
Can I calculate my age on a past or future date?
Yes. Change the Age on field from today to any valid date on or after the date of birth.
How are February 29 birthdays handled?
The default everyday convention uses February 28 in non-leap years. Advanced Options lets you use March 1 instead because conventions and legal rules can vary.
What is chronological age for an assessment?
Chronological age is age on the test or assessment date, commonly written as years;months;days. Some assessment manuals require a special 30-day borrowing method, so select the convention required by the applicable manual.
Can I calculate the age difference between 2 people?
Yes. Choose Age difference, enter both birth dates, and the calculator will show the exact fixed gap and identify the earlier date.
Are hours and minutes exact?
They are approximate because the calculator uses calendar dates without a birth time or birth time zone. Completed days are exact for the entered dates.
Does DailyUseCalc save my date of birth?
No. The calculation runs in your browser. The calculator does not automatically save the dates or place them in the page URL.
Can I download or share the result?
Yes. After calculating, you can copy the result, print a formatted report, download a PDF, or open your device share menu.
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