Age Calculator
Calculate Age reports years, months, and days between a date of birth and an Age at date you can change. The detail line adds the total number of days.
How to use
- Set Date of birth.
- Set Age at date. On load, an empty Age at date is filled with today. Change it when you want age on another day.
- Click Calculate Age. The result reads years, months, and days. The detail line shows total days and the days until the next birthday, counted from the as-of date.
When it helps
Change Age at date for a past birthday, a future eligibility day, or any as-of date other than today. Years, months, and days borrow across month lengths, so the result is a calendar age rather than a decimal year. Total days is the straight whole-day span between the two dates.
For a gap that should not be phrased as an age, the date calculator reports days and whether the end is earlier, later, or the same day. Body size is separate: the BMI calculator uses weight and height, not a birth date.
Limits
If Age at date is before the date of birth, the result says Invalid range and does not show a negative age. An empty birth date says Enter date of birth.
On the birthday itself, the next-birthday count moves to the following year, so the detail line does not say zero days. The page does not show hours, and it does not apply a time zone beyond the calendar dates you choose.
Questions
Can the as-of date be something other than today?
Yes. Age at date is editable. Years, months, days, and the total day count all use that date.
What else is on the detail line?
Besides total days, it counts days until the next birthday from the Age at date. On the birthday, that count points at next year.
Does it show a decimal age?
No. You get whole years, months, and days, plus total days. There is no figure such as 30.5 years.