Age Calculator

Defaults to today's date if left empty.
Everyday Life

The Age Calculator works out exactly how old you are in years, months and days from your date of birth. You can also set an 'age at' date to find how old you were (or will be) on any other day, plus your age in total months, weeks and days.

Formula

Age = whole years, then remaining months, then remaining days between the two dates
  • Age is counted as whole years first, then the remaining whole months, then the leftover days, the way people normally state an age.
  • Month-end dates are handled carefully so, for example, 31 Jan to 28 Feb counts as a full month.
  • Leave the 'age at' date blank to use today's date.
  • Totals in months, weeks and days count the entire span between the two dates.

Example Calculation

Inputs
  • Date of birth (or start date): 2000-01-01
  • Age at date (leave blank for today):

For a date of birth of 1 January 2000 with the 'age at' date left blank, the calculator shows your exact age today in years, months and days, plus the totals in months, weeks and days.

Frequently asked questions

How does the Age Calculator work?
It counts the whole years, then months, then days between your date of birth and the chosen date, the way ages are normally stated.
Can I find my age on a future or past date?
Yes. Enter an 'age at' date to see how old you were, or will be, on that specific day. Leave it blank to use today.
How are month lengths handled?
The calculator adjusts for different month lengths and leap years, so partial months are counted accurately.
What do the total months, weeks and days mean?
They express the same age as a single running total — the full number of months, weeks or days between the two dates.
Does it include the birth day itself?
Age is measured from the date of birth to the chosen date, so your age increases on each birthday.

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