Age Calculator — Exact Age, Days & Next Birthday
Calculate exact age in years, months and days, total elapsed time, age on any date, and the countdown to the next birthday.
Calculate your exact age
Enter a birth date and any comparison date to see calendar age, elapsed time, the next birthday, and where that date falls on a clear timeline.
Your age timeline
How this age was calculated
Birthday details
Calendar age, not an average year estimate
This calculator counts completed calendar years first, then completed calendar months, then remaining days. It does not divide elapsed days by 365, so month lengths and leap years are handled correctly.
Age on any past or future date
The comparison date can be today, a historical event, a deadline, or a future birthday. This is useful for forms, eligibility checks, school dates, anniversaries, and planning milestones.
Elapsed days, weeks, and months
Total days are the exact number of midnights between the two dates. Total weeks are shown as complete weeks plus remaining days. Total months count completed calendar months rather than treating every month as the same length.
February 29 birthdays
In non-leap years, institutions may treat a leap-day birthday as February 28 or March 1. Choose the convention relevant to your purpose. Legal eligibility rules vary by jurisdiction.
Frequently asked questions
How old am today?
Keep “Age on date” set to today. The main result shows completed years, months, and days, while the detail cards show total elapsed days and the countdown to the next birthday.
Why is age not simply days divided by 365?
Calendar years contain 365 or 366 days and months have different lengths. Official ages normally advance on calendar anniversaries, so calendar arithmetic is more accurate than an average-year conversion.
Does the calculator include the birth date as day one?
No. Elapsed time is zero on the birth date and increases after each completed day, matching standard date-difference calculations.
Can I calculate age at a past date?
Yes, provided the selected comparison date is not earlier than the birth date.
Method and privacy
All calculations run locally in your browser; entered dates are not submitted by this tool. Calendar calculations use date-only UTC arithmetic to avoid daylight-saving-time errors. Always verify legal age or eligibility with the relevant authority.
