Work out an exact age on any date
Enter a date of birth and the calculator reads your device date to give the age today. Change the "age on this date" box to ask a different question: how old someone was on a school start date, at a past event, or how old they will be on a date next month. The answer comes as whole years, then months, then days.
Underneath the main result you get the same span in other units: total months, total weeks and total days lived. These are handy for milestones such as the 10,000th day, or for filling in a form that wants age in months. The page also names the weekday of the birth, which is often a surprise, and shows the next birthday with the number of days left.
Leap-day birthdays need a rule, so here it is: a person born on 29 February is counted as having their birthday on 1 March in years that are not leap years. On 28 February of a non-leap year they have not yet had it. On 1 March they have.
Everything runs in your browser. The date of birth is not sent anywhere and nothing is saved unless you copy the link yourself. The tool measures calendar time only and does not interpret the number in any other way.
Worked examples
Questions about this tool
Can I find the age someone will be on a future date?
Yes. Put the future date in the "age on this date" box and the result shows the age on that day, counted the same way.
Why do months and days sometimes look uneven?
Months have different lengths, so the day count is measured from the last whole month. The total days figure is the exact span and never has this issue.
How is a 29 February birthday handled?
In non-leap years the birthday is taken as 1 March. In leap years it is the real 29 February.
Is my date of birth stored?
No. The sum is done on your device and nothing is uploaded.
Can I find an age on a cut-off date for an exam or form?
Yes. Enter the date of birth, then type the cut-off date into the age on this date box. The result is the exact age in years, months and days on that day, which is what many exam, school entry and application forms ask for.