Calendar age uses real calendar units
The result uses complete calendar years, months, then days instead of dividing total days by 365.
048 · DATE & TIME
Age & Elapsed Life Calculator
Use a date of birth and as-of date to see exact calendar age, year age, days since birth, and the time remaining until the next birthday.
LOCALAge calculations run only in your browser.
LOCALYour date of birth and as-of date are calculated only in this browser and are not sent to or stored on a server.
AGE WORKSPACE
Choose a date of birth
RESULT
Choose a date of birth to see age and elapsed-life results instantly.
HOW TO USE
How to use
- 01
Choose a date of birth.
- 02
Confirm the as-of date or change it when needed.
- 03
Review calendar age, year age, days since birth, and next birthday.
- 04
Copy the result if needed, or reset for a new calculation.
AGE GUIDE
How to read age and elapsed life accurately
Separate calendar age from year age and use explicit rules for leap years, month ends, February 29, and elapsed days.Year age is separate
Year age is the as-of year minus birth year, so it is shown separately from birthday-based calendar age.
Days since birth use elapsed days
The same date is 0 days, using the actual Gregorian date difference.
Next birthday is immediate
The tool uses this year's birthday when it has not passed, otherwise next year's birthday.
February 29 policy is fixed
A February 29 birthday is treated as February 28 in non-leap years, consistently across results and help text.
IMPORTANT NOTES
Important notes
- Results use calendar dates and are not a sole basis for legal eligibility, insurance, or medical decisions.
- The supported service range is 1900-01-01 through 2100-12-31.
- A future date of birth is rejected instead of being displayed as a normal result.
- Raw input dates and calculated results are not sent to a server or Analytics value.
FAQ
Frequently asked questions
01Why are calendar age and year age different?+
Calendar age uses completed years, months, and days from the birthday; year age is the as-of year minus birth year.
02Can I change the as-of date from today?+
Yes. Today is the default, but you can choose another date within the supported range.
03Is the birth date counted as day 1?+
No. This uses elapsed days, so the birth date itself is day 0.
04How is a February 29 birthday handled in a non-leap year?+
This tool consistently treats February 28 as the birthday in non-leap years.
05Are leap years and month ends handled?+
Yes. Calculations use Gregorian leap-year and month-length rules.