What is an age calculator?
An age calculator tells you exactly how old someone is on a given date, in years, months and days. It is handy for forms that ask for an exact age, for eligibility rules with age limits, or just out of curiosity about how many days you have been alive.
Counting age by hand is error prone, because months have 28 to 31 days and leap years add an extra day. This calculator walks through the real calendar instead of using averages.
How the age is counted
First, it counts the whole months from your date of birth to the "Age on" date, then splits them into years and months. The days left over after the last full month are the days in your age. Totals for months, weeks and days are counted on the same calendar.
Two calendar rules matter. If your birth day does not exist in a month, for example the 31st in a 30-day month, the last day of that month counts. And if you were born on February 29, February 28 counts as your birthday in other years.
How to use the age calculator
- 1Enter the date of birth.
- 2Leave "Age on" set to today, or pick another date to check an age in the past or future.
- 3Read the age in years, months and days, plus the totals and the countdown to the next birthday. Copy the result or a link to share it.
Frequently asked questions
How is my exact age calculated?
The calculator counts whole years and months forward from your birth date on the calendar, then counts the days that are left. It uses the real length of every month and year instead of averages like 30 days per month or 365.25 days per year.
What if I was born on February 29?
In years without a February 29, this calculator counts February 28 as your birthday. Some laws and organizations use March 1 instead, so check the local rule if a legal deadline depends on it.
How are birthdays at the end of a month handled?
If a month is shorter than your birth day, the last day of that month counts as your monthly anniversary. Someone born on January 31 is one month older on February 28 or 29.
Can I calculate an age on a past or future date?
Yes. Change the "Age on" date to any date after the date of birth, for example to check an age on a deadline or at a future event.
Do time zones or the time of day change the result?
No. The calculator only compares the calendar dates you enter, so time zones and daylight saving time have no effect. Your dates stay in your browser.