Age Calculator
Your exact age in years, months and days, plus the next birthday.
Enter a date of birth to see the age.
Loading today's date.
Working out an age sounds like subtraction until you try it. The years are simple. The months and days are not, because months are different lengths and February keeps changing its mind.
This counts it the way people say it out loud: full years first, then the months that have completed since the last birthday, then the days left over. A birthday only counts once the day of the month has come round, so the number matches what you would tell someone.
It also gives the same age in months, weeks, days and hours, tells you which day of the week the birth date fell on, and counts down to the next birthday. Set the second date to something other than today to work out how old somebody was at a particular moment.
How the totals are worked out
The totals come from the exact number of days between the two dates. Weeks are those days divided by seven and rounded down, hours are the days multiplied by 24, and months are the full years times twelve plus the extra months.
The hours figure counts whole days only. It does not include the hours since midnight or the time of day you were born.
A worked example
Someone born on Wednesday 31 January 1990 is 36 years, 7 months and 24 days old on 24 September 2026. The months stop at 7 because the 31st has not come round yet this month: the seventh full month since the birthday ended on 31 August, and 24 days have passed since then.
That is 13,385 days, 1,912 weeks, 439 months and 321,240 hours. The next birthday, on 31 January 2027, is 129 days away.
Mistakes people make with ages
Subtracting the years only. 2026 minus 1990 is 36, which is right for someone born in January and wrong for someone born in December who has not had this year's birthday yet.
Expecting the hours to be exact. The hours figure is whole days times 24. For an age to the hour you would need the time of birth and the time zone it happened in.
Measuring to the wrong date. By default the age is worked out to today. For an age on a particular day, such as the start of a school year or an application deadline, change the as-of date.
Time you can measure is time you can manage.
Counting the days is easy once you have a date. Counting where the hours went is harder. PomoTodo records your working time as it happens and shows you the week you actually had, not the one you remember.
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More tools
Add or subtract days from a date, or count days between two.
Weeks from a date, weeks between dates, and week numbers.
Days, hours and minutes until whatever you are waiting for.
Working days between dates, or when a deadline lands.
Questions
How do I calculate age from a date of birth?
Enter the date of birth and the age appears straight away. By default it is measured to today, but you can change the second date to work out how old someone was, or will be, on any other day.
How is the age worked out exactly?
Full calendar years are counted first, then whole months since the last birthday, then the remaining days. A month only counts once the same day of the month arrives, so somebody born on the 20th is not a month older until the 20th comes round again.
What happens with a 29 February birthday?
In years that are not leap years the birthday is treated as 28 February. Legal conventions differ, and some places use 1 March instead, so check the local rule if a legal age depends on it. Either way, the age still increases every year rather than every four.
Can I find out what day of the week I was born?
Yes, it is shown under the age as soon as you enter a date of birth. The calculation is exact for any date in the Gregorian calendar.