Select your birth date from the calendar
Select the current date or leave as today
When to use an age calculator
An age calculator answers “how old am I?” or “how old was I on a given date?” by counting full years, then months, then days between two calendar dates. It is handy for school forms, event planning, genealogy notes, and milestone tracking.
Results are chronological age only. Legal eligibility (voting, contracts, benefits) may depend on rules in your country or state—confirm with official sources when it matters.
What is chronological age?
Chronological age is the time elapsed since birth, usually expressed as years, months, and days. It differs from biological age or legal age rules used for voting, contracts, or benefits.
This calculator subtracts a birth date from a target date using calendar logic—accounting for different month lengths and leap years—rather than dividing total days by 365.
How the calculation works
- Enter the birth date and the date you want age calculated as of (today by default).
- Count full years from birth year to target year, adjusting if the birthday has not occurred yet in the target year.
- Count remaining months and days with borrow logic when days in a month are insufficient.
- Display the result as years, months, and days.
Worked examples
Age as of today
- Birth date: March 15, 1990
- Target date: June 21, 2026
Result: 36 years, 3 months, 6 days. Useful for forms that ask for exact age.
Age on a future event
- Birth date: January 10, 2010
- Target date: January 10, 2030
Result: exactly 20 years—helpful for eligibility planning tied to a birthday.
Practical uses
- •School or sports registration forms that ask for age in years and months
- •Genealogy and family history notes
- •Event planning (“how old will they be at the wedding?”)
- •Verifying milestone birthdays
Limitations
- !Does not determine legal age of majority or jurisdiction-specific rules
- !Uses Gregorian calendar only
- !Not for medical gestational age calculations
References
- National Institute of Standards and Technology (NIST) — Calendar and time standards
How This Calculator Works
Pick two dates
Choose a birth date and the date you want age calculated as of.
Subtract calendar-style
Years, months, and days are computed with borrow logic for uneven months.
See the breakdown
Results show your age as years, months, and days—not a single total-days count.
What is Age Calculator?
An age calculator is a tool that finds the exact time between a birth date and a target date, reported as full years, then months, then remaining days. It uses calendar-based subtraction, so uneven month lengths and leap years are handled automatically rather than approximated.
Enter a birth date and target date to get a years-months-days breakdown. The tool uses standard calendar subtraction so month lengths and leap years are reflected in the result.
Any target date
Calculate age as of today or any other valid date you choose.
Leap years
Gregorian calendar rules are used when counting between dates.
Private
Dates stay in your browser—no account or server storage.
Last updated: · Published:
How to Use This Tool
Enter birth date
Select your date of birth using the calendar picker.
Set target date
Choose the date to calculate age as of—defaults to today.
Calculate
Click Calculate or wait for automatic results when both dates are set.
Read your age
View the breakdown in years, months, and days.
Pro Tips
- Useful for forms, milestones, and “age on date” questions
- Leap years are handled automatically in the calendar math
- Set a future target date to see age on an upcoming birthday or event
- For legal purposes, rely on official ID and local rules—not this tool alone
- All calculations run locally in your browser