Guide · Updated November 2026 · How we check our numbers
How to Calculate Your Exact Age in Years, Months and Days
Working out your age in whole years is easy: subtract your birth year from this year, and take one off if your birthday has not happened yet. Getting the exact age in years, months and days takes a little more care, because months have different lengths.
The three-step method
- Years: count full years from your birth date to the most recent birthday.
- Months: from that birthday, count full months to the latest "month-day" that is not after today.
- Days: count the remaining days up to today.
Worked example
Born March 15, 1990, and today is November 14, 2026:
- March 15, 1990 → March 15, 2026 = 36 years
- March 15 → October 15, 2026 = 7 months (November 15 has not arrived yet)
- October 15 → November 14 = 30 days (October has 31 days)
So the exact age is 36 years, 7 months and 30 days.
Why months cause mistakes
Counting "30 days per month" drifts quickly, because months have 28 to 31 days. Always count real calendar months, then real days — that is exactly what our calculator does.
Leap years and February 29 birthdays
A year is a leap year if it is divisible by 4, except century years, which must also be divisible by 400. That is why 2000 was a leap year but 1900 was not. People born on February 29 legally turn a year older on February 28 or March 1 in common years, depending on the country; many celebrate on February 28.
Age in total days
Sometimes you need the total number of days lived — for example for a "10,000 days old" celebration. Subtract the dates directly; the calculator does this instantly and also shows weeks, hours and minutes.
Try the calculators
This guide is general information, not professional advice.