CalcVane

Age and date calculator

Age and dates, to the day.

Get an exact age, or count the days between any two dates. Leap years and month lengths are handled for you.

Age calculator

Exact age

February 29 rule. If you were born on February 29, CalcVane counts your birthday on February 28 in years without a leap day. The same rule applies to any date a month doesn’t have, such as the 31st: the last day of that month is used. Legal ages can follow different rules, so check them where it matters.

Days between dates

How age is counted

Age is the number of whole years since your birth date, then the whole months since your last birthday, then the remaining days. The day count between dates is the number of midnights crossed, which is why the end date isn’t counted unless you turn on the toggle. Turn it on for things like a hotel stay counted by days present, or an event that runs “from the 1st to the 10th inclusive”.

Formula

Years = whole years from birth date to the "as of" date Months = whole months from the last birthday Days = remaining days after those months Days between = end − start (+ 1 if the end date is included)

Worked example

Someone born on May 15, 1990 is 36 years, 5 months and 20 days old on November 4, 2026. They were born on a Tuesday. You can check the weekday with any perpetual calendar, which is a quick way to confirm you typed the right birth date.

When to use it

Sources

Last reviewed: . Results are for general information; check important figures yourself.