Age Calculator
Work out exact age in years, months and days from a date of birth, plus total days and weeks lived and the days until the next birthday.
New: please check your results.
- Age
- 36 years, 5 months, 12 days
- In whole years
- 36 years
- In months
- 437 months
- In weeks
- 1,902 weeks
- In days
- 13,314 days
- Next birthday
- 15 May 2027
- Days until then
- 200 days
- Born on a
- Tuesday
What it does
Find exactly how old someone is, in years, months and days, from their date of birth. It also shows the age as total months, weeks and days, the date and countdown to the next birthday, and the day of the week they were born. Change the second date to find an age on any day.
How to use it
- Date of birth
The date the person was born.
- Age on
The date to work out the age on. It starts as today; change it to find an age on a past or future date, such as a deadline for an age limit.
Common uses
- Checking someone's age on a cut-off date for school, sport or a licence.
- Working out exactly how many days old a baby is.
- Counting down to a birthday.
- Counting the days between any two dates. Try the Days Between Dates Calculator
The formula
Years = the number of birthdays passedMonths = whole months since the last birthdayDays = days since that many months after the last birthdayWhere:
- Total days
- the date minus the date of birth, counting every leap day
Someone born on 29 February is treated as having their birthday on 1 March in other years, as UK law counts it.
Worked example
Born on 15 May 1990, on 26 October 2026:
- Birthdays passed: 36
- Whole months since the last one: 5, plus 11 days
- Age: 36 years, 5 months, 11 days
That's 13,313 days in all. They turn 37 on 15 May 2027, in 201 days.
Questions people ask
How is age worked out for someone born on 29 February?
In years without a 29 February, UK law treats their birthday as 1 March, so they turn 18 on 1 March. Some other countries use 28 February instead.
Why do months and days sometimes look uneven?
Months have different lengths, so ages count whole calendar months first and then the days left over. From 31 January, one month on is the last day of February.
Does it count today?
The age is how much time has passed, so on someone's birthday it shows exactly the new number of years with 0 months and 0 days.
Last checked 26 October 2026