What this calculator does
The Age Calculator works out a person's exact age in years, months, and days between a date of birth and any later date, which by default is today. It also shows the same age expressed as total months and days, and the total number of days lived so far.
It is handy for official forms and visa or school applications, for counting down to birthdays and milestone dates, and for checking ages against age limits in job, sport, or retirement rules. The counting is calendar-accurate — it respects leap years and the different lengths of months — and the page works in English, Arabic, and Spanish.
How to use the Age Calculator
- Enter the date of birth in the first field, either by typing it or using the date picker.
- Optionally enter an "age at" date in the second field. Leave it empty to calculate the age as of today.
- Click "Calculate age" to see the result below the button.
- Read the result: the first line shows the age in years, months, and days; the second line shows the same age in total months and total days.
- Change either date and click again for a new result.
How the calculation works
The calculator counts complete calendar units. It subtracts the birth date from the target date year by year and month by month, borrowing days from the previous month whenever the day of the month is not reached yet. Because months have 28, 29, 30, or 31 days, the number of days left over depends on which months are involved.
For example, someone born on 29 February (a leap day) has a birthday on 1 March in non-leap years under this counting, since 29 February does not exist that year.
Example
For a birth date of 15 March 2000 measured on 19 October 2026:
- Age: 26 years, 7 months, 4 days
- That is 319 months and 4 days, or about 9,714 days in total
A real-life case: a form asks for your age "as of 1 January" for a sports category. Enter your birthday and set the age-at date to 1 January to get the exact figure the form needs.
Frequently asked questions
Why does my age in days here differ from age × 365?
Because years are not all 365 days long — leap years add a day and month lengths vary. The calculator counts real calendar days, which is the accurate figure.
How are leap-day birthdays handled?
People born on 29 February are counted as turning a year older on 1 March in non-leap years, which is the most common legal convention.
Can I calculate the age at a future date?
Yes. Set the "age at" date to any future date, for example to see how old someone will be on a coming birthday or deadline. The only restriction is that the target date cannot be before the date of birth.
Which time zone does the calculator use?
It uses your device's local calendar date. "Today" means the date where you are right now, so the result matches what you see on your calendar.
Does it work for babies and very young children?
Yes. The result shows months and days precisely, which is the usual way to express the age of infants.
Is my data saved or sent anywhere?
No. The calculation runs entirely in your browser, and your dates are never stored or sent to a server.
Related calculators
Other free calculators commonly used with this tool: Hijri–Gregorian Date Converter, Percentage Calculator, and Simple Arithmetic Calculator.
Want a deeper walkthrough? Read our age calculation guide.