Age & Date Calculator
Calculate age, date differences, and more
About Age & Date Calculator
Calculates exact age in years, months, and days from a birth date, or the number of days between any two dates — more precise than the rough mental math of subtracting years, which doesn't account for whether the birthday has actually happened yet this year.
Enter a birth date (or two dates for a general date difference), and the calculated age or interval appears immediately.
This is also useful for far more than birthdays — counting days until a deadline, the exact duration of an event, or how many days pregnant someone is all work the same way, just by entering the relevant two dates instead of a birth date and today.
Watch: Age & Date Calculator in Action
- Can I use this for something other than calculating a birthday age?
- Yes — entering any two dates instead of a birth date works the same way, useful for counting days until a deadline, the exact duration of an event, or how many days pregnant someone is.
- How does it handle a 29 February birthday?
- In years that are not leap years, the next birthday is counted on 1 March, and a note under the result says so. Your current age in years, months and days is still worked out from the real birth date you entered.
- What changes when I switch on Include the end date?
- By default the start day is counted and the end day is not, so 1 June to 2 June is 1 day. With Include the end date on, both ends count and the same pair gives 2 days. The business-day count follows the same rule.
- Are weekends and public holidays excluded?
- With Business days only (Mon-Fri) switched on, Saturdays and Sundays are skipped. Public holidays are not excluded, and the page states this under the result. If holidays apply to you, subtract them from the figure yourself.
- What happens if I enter a birth date in the future?
- No age is shown. Instead the tool reports that the date is in the future and gives the number of days between today and that date, which can be handy for counting down to an expected date.
- Why might another calculator differ by a day or a month?
- Methods vary. This one adds whole calendar months to the start date and then counts leftover days, using local dates with no clock times. Other sites may assume 30-day months, use time zones, or include the final day, and each choice shifts the answer.
How to use Age & Date Calculator
The page has two buttons: Age and Days between two dates. In Age mode, click the Date of Birth field and choose a date from the calendar or type it. The result shows your age in years, months and days, followed by total months, total weeks and total days, the weekday you were born on and the number of days left until your next birthday.
In Days between two dates mode, fill in From and To; To starts as today's date. Switch on Include the end date to count both ends, or Business days only (Mon-Fri) to count weekdays. The large number is the day count, and below it the gap is also written as years, months and days, and as weeks plus leftover days. If you enter the dates in the wrong order, the tool swaps them and says so.
When to use it
Use Age mode for forms that ask for exact age, for working out how old a child is in months, or for finding the weekday of a birth date. Use the between-dates mode to count the days to a deadline, measure a notice period, see how long ago something started, or check how many working days lie between two dates in a project plan.
When not to use it
It is not suited to legal age checks that depend on one country's rules or on a specific hour of the day, because it works with calendar dates only and ignores clock times. It also cannot exclude public holidays from business-day counts, so for leave or delivery planning, compare the result with your local holiday calendar yourself.
Tips for best results
To count the days remaining until an event, use the between-dates mode with today in From and the event in To, rather than Age mode, which for a future date only reports how far away it is. Turn on Include the end date when both the first and last day count, such as a booking that covers every calendar day of its span.
Limitations
Dates are read as calendar days in your device's local time, so results depend on your device clock being correct. The months-and-days breakdown adds whole calendar months to the start date first and then counts leftover days, so unequal month lengths can differ slightly from other methods. Business days skip only Saturdays and Sundays. This is general information and not legal or professional advice.
Privacy
A date of birth is personal, so it matters that the calculation runs entirely in your browser from the dates you type. Nothing is saved, no account is needed and the birth date is not sent to the site. Only a usage count that names the tool is reported, and it contains none of your dates.
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