Calculate an exact age in years, months and days from a birth date to a selected date, plus total weeks, months and days.
Calendar-day differences, business-day counting, days-until questions and date arithmetic.
Enter a birth date and the date on which you want to know the age. The result gives completed years, months and days plus total elapsed days, weeks and completed months.
The calculator also finds the next birthday after the selected “age on” date and shows the number of days remaining. This makes it useful for age-at-date questions as well as birthday countdowns.
Exact calendar age is not simply total days divided by 365 because months and leap years have different lengths. The calculator compares calendar years, months and days directly.
Use days between dates for a pure date difference, weeks between dates for a weekly span, or days until a date for a countdown.
Someone born on June 15, 2000 turns 26 on June 15, 2026. On June 14, 2026, they are still 25 because that year's birthday has not yet occurred. Subtracting calendar years alone would overstate their age one day before the birthday.
Edge cases: exact years, months, and days depend on the two dates and calendar month lengths. For February 29 birthdays, legal conventions for non-leap years may vary by jurisdiction; the calculator provides a calendar-based result, not legal age advice.
Yes, as long as the selected date is on or after the birth date.
The exact age uses the real birth date. For a next-birthday countdown in a non-leap year, February 29 is treated as the last valid day of February.
Enter your birth date and choose the date you want to measure against. The calculator reports completed years, months and days, which is more precise than simply dividing the number of days by 365.
An exact age is based on calendar dates. For example, someone can be 20 years old while also being 20 years, 7 months and 12 days old. The extra months and days show how far the person is past the last birthday.
| Question | Use this result |
|---|---|
| How old am I today? | Exact age in years, months and days |
| How old was I on a past date? | Set the “age on” date to that past date |
| How old will I be on a future date? | Set the “age on” date to the future date |
| How many days old am I? | Use the total-days result |
| How long until my next birthday? | Use the next-birthday countdown |
For other calendar calculations, use the Add or Subtract Days Calculator or browse the Dates & Deadlines topic hub.
See how formulas, sources and limitations are handled across ERICH Calculators.