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Calculate exact age between two dates

Get age in years, months and days, plus totals in weeks, days and hours — leap years handled correctly.

The precision forms ask for

School admissions, pensions and eligibility rules often need age in years, months and days on a specific date, not just a birth year.

Try this tool

Any two dates, not just today

Set the reference date to a deadline or an exam day to check whether someone qualifies on that date.

Open Timer & Stopwatch

Countdowns and milestones

See days until the next birthday and totals in weeks or hours — the numbers people actually enjoy sharing.

Open Online Abacus

Step-by-step guide

How to use Age Calculator?

Find someone's exact age in years, months, days, hours or minutes from any date.

Step-by-step instructions

1
Enter the date of birth.
2
Enter (or leave as today) the target date.
3
See the exact age broken down into years, months, days.
4
View additional units like total weeks, days or hours lived.

Benefits

Precise breakdown down to seconds.
Handles leap years correctly.
Works for future or past dates.
Instant, no signup.

Who is it for?

Parents tracking a baby's exact age
Job applicants checking age eligibility for exams
Anyone curious about how long they've lived

Câu hỏi thường gặp

Enter your birth information in the left column: type or choose Date of Birth (use the YYYY-MM-DD field or the native calendar picker), optionally add Time of Birth (HH:MM) and select the Time Zone dropdown if you were born in a different zone. Click the blue Calculate Age button (or press Enter) and the tool displays years, months, days, hours, minutes and seconds; click Copy Result to copy the formatted string. If you only need years/months/days leave Time blank; to update live, enable the Enable Live Countdown toggle to refresh every second.

The tool accepts ISO (YYYY-MM-DD), MM/DD/YYYY and DD/MM/YYYY — choose your preferred format from the Date Format selector above the input or type ISO to avoid ambiguity. If you paste ambiguous text like 03/04/2005 the calculator uses the selected format; if no format is chosen it defaults to MM/DD/YYYY in Chrome and DD/MM/YYYY for some locales in Safari, so explicitly set the selector to be safe. You can also paste natural forms such as Jan 3 1990, but the safest option for cross-browser consistency is YYYY-MM-DD.

Yes — there is an optional Time of Birth field (HH:MM, 24-hour or AM/PM accepted) and a Time Zone dropdown that lists major zones (e.g., America/New_York, UTC, Europe/London). When you include time and zone the tool computes exact age down to seconds and correctly accounts for daylight saving transitions; leaving zone blank uses your browser’s local timezone. Note that enabling seconds/continuous update increases CPU usage on phones; toggle Live Countdown off to reduce battery drain.

Switch to the Age Between Two Dates tab, enter a Start Date and End Date (or use the Swap Dates button to invert them), then click Calculate Range to get an exact difference in years, months, days and total days. The tool shows both a human-readable breakdown and a Total Days / Total Hours summary; use Copy Result to put the formatted text on your clipboard. If End Date is left blank it defaults to today; negative ranges show an Invalid Date error and you'll see the red Clear button to reset inputs.

Click the Birthday Countdown tab, enter your Date of Birth and optionally Time, then press Show Countdown — the tool displays days/hours/minutes/seconds to your next birthday and the computed Next Birthday Date. Use Export .ics to download a one-event iCalendar file (next_birthday.ics) that imports into Google Calendar, Outlook and Apple Calendar; on mobile Safari the file downloads to the Files app before import. For privacy this export is created client-side; enabling Live Countdown will update the on-page timer every second but may keep your device awake.

If your birth date is Feb 29 the calculator treats your age-in-years according to common anniversary rules: for age increments it counts a year on Feb 28 in non-leap years so Age in Years increments on Feb 28, while the Next Leap-Day birthday is shown as Feb 29 on the next leap year. The birthday countdown by default targets Feb 28 in non-leap years for annual reminders, but the Next Leap-Year field will also show the actual next Feb 29 if you need that date. This behavior is described under the Feb 29 note below the inputs so you can choose which anniversary to export.

Calculations are performed in your browser with JavaScript and no date/time inputs are sent to our servers unless you click Export .ics or use the optional Share Link button, which encodes dates in the URL fragment only. There is no account required, no sign-up, and the site does not store personal DOBs on the server by default; Export .ics will download a file to your device and Share Link explicitly creates a short URL that you choose to copy. Note that if you use the Share Link your browser may record the URL in history; clear it if you need extra privacy.

Desktop Chrome and Firefox show the inline calendar and accept typed ISO dates; Safari on macOS and iOS uses the native date picker which prevents typing the year directly in some versions — tap the year to scroll quickly. Internet Explorer does not support input type=date reliably, so the tool falls back to a text field that requires YYYY-MM-DD; if you see an Invalid Date error in IE, re-enter using YYYY-MM-DD. On older Android devices the live countdown can stutter due to CPU throttling — disable Enable Live Countdown to get a static calculation.

Invalid Date appears when you enter a non-recognized string or a year outside the accepted range (0001–9999); fix it by using YYYY-MM-DD or selecting a valid date from the picker. If you get a negative age, check that you didn't swap Date of Birth and Comparison Date — use Swap Dates to correct order or the Clear button to start over. If the countdown won't start on mobile, confirm Live Countdown is enabled and that your browser allows background activity; otherwise use the static Show Countdown result.

The calculator accepts dates in the Gregorian calendar from year 0001 through 9999 (ISO 8601 range) and will show an Invalid Date error outside that range; performance is essentially instant for single calculations. On low-memory phones, enabling Live Countdown (updates every second) and adding seconds precision may cause the browser tab to be throttled or drained faster, so disable Live Countdown for long-running pages. Very large batch operations (copying many results) are not supported — the UI is optimized for single or occasional calculations, not bulk processing.

Yes — the tool is free to use with no required account, no hidden paywall and no watermark on exported .ics files; you will see unobtrusive banner ads that fund hosting but they do not block functionality. There are no feature-locked premium tiers and exports (copy, .ics) are available without signup; however automated API access is not provided. If you need programmatic access consider using a local script (Python) — the web UI is built for interactive use.

For fast one-off calculations use the Date of Birth + Calculate Age flow and click Copy Result — that’s quicker than writing Excel DATEDIF formulas which often need extra checks for leap years or DST. If you want reproducible scriptable runs, a small Python script using dateutil gives the same precision, but this web tool handles edge cases like leap day anniversaries, time zones and DST without coding. Pro tip: set Date Format to YYYY-MM-DD for cross-browser consistency, use Export .ics to add upcoming birthdays to calendars, and toggle Live Countdown sparingly on mobile to save battery.

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