How to work out age in years, months, and days
Age in years alone hides a lot. Two people born in the same year can be almost a year apart in age, so years, months, and days together give the true gap.
Pick a date of birth, day first, then month, then year. Pick a second date if you want age on that date, or leave it blank for today. The result shows the gap in years, months, and days, plus the total days between the two dates.
Months are not all the same length, so the calculator borrows days from the previous month when the day count goes below zero, and borrows months from the year in the same way. That is why the total days and the years-months-days figures can look different at first glance: one is a straight count of days, the other is a calendar count.
Use the total days figure when you need an exact count, for example for a form that asks for days. Use years, months, and days when you need an age people can read at a glance.