Age Calculator — Free Online Birthday Age & How Old Am I Tool

Age Calculator — Free Online Birthday Age & How Old Am I Tool. Free online age calculator. Find your exact age in years, months and days, total days and weeks, and see how many days until your next birthday.

Use our free age calculator to find your exact age in years, months, and days from any date of birth.

Whether you want to know how old am I, check someone's age for legal or medical purposes, or calculate an age from a historic date, our tool gives instant, precise results.

Simply enter a birth date and a comparison date (today by default) and get your exact chronological age breakdown — years, months, days, total days, total weeks, and days until your next birthday. Your dates never leave your browser.

Related: Days Between Dates, ETA Calculator. Our birthday calculator handles all edge cases — leap years, month-end boundary dates, and cross-century calculations.

Beyond the standard date of birth calculator output, we show total days and total weeks lived, and count down to your next birthday celebration.

Perfect for HR teams verifying employee ages, parents tracking milestones, or anyone curious about calculate age from a specific past event. This age calculator online runs entirely in your browser — 100% free, private, and instant.

Frequently asked questions

How do I find out how old I am with this age calculator?

Pick your birth date in the Date of Birth field. The Compare To field defaults to today's date in your own time zone, so the result box immediately shows your exact age in years, months and days, together with the total days lived, total weeks and the number of days until your next birthday.

Can I calculate someone's age on a specific date instead of today?

Yes. Change the Compare To date to any past or future date, for example a school cut-off date or a retirement date, and the age is recalculated for that day. This is handy for checking how old someone was, or will be, on a given date.

How are the years, months and days counted?

The tool counts the whole years and months up to the last monthly anniversary of the birth date, then the days left over, so the result reads the way people usually state an age, such as 25 yr 3 mo 12 d. A birth day missing from a month, like the 31st or 29 February, falls on that month's last day. Total Days is the full number of days between the two dates.

What does Days Until Next Birthday show?

It counts the days from the Compare To date to the next anniversary of the date of birth. When the birthday falls on the Compare To date itself, a birthday cake icon is shown instead of a number. For a 29 February birthday, 28 February is used in common years.

Is my date of birth sent anywhere?

No. The age calculation runs in your browser with JavaScript, and the dates you enter are not uploaded or stored.

How to use this online tool

Age Calculator — Free Online Birthday Age & How Old Am I Tool is designed for fast browser workflows when you need to format, validate, convert, decode, encode, generate, or inspect data without opening a heavy desktop app. Start with the input field or visible options, review the result, then copy or download the output for the next step.

Private processing in your browser

Age Calculator — Free Online Birthday Age & How Old Am I Tool keeps the normal processing step local in your browser. That is useful for code snippets, tokens, documents, configuration values, text samples, and other material that should not be sent to a remote service unless you explicitly choose to share it.

When this tool is useful

Use Age Calculator — Free Online Birthday Age & How Old Am I Tool for repeatable developer tasks, technical documentation, QA checks, quick conversions, debugging, content cleanup, and internal team workflows. The page focuses on clear inputs, immediate feedback, and output that is easy to reuse in code, reports, tickets, emails, or notes.

Practical tips

Before copying the final result, check important details such as spacing, casing, filenames, encoding, token structure, line breaks, or output format. Small checks prevent mistakes when the result is reused in source code, API requests, documentation, spreadsheets, or shared files.