Does the online alarm clock work offline?

Yes! Once the page is loaded, alarms are synthesized using the Web Audio API and work even if your WiFi drops.

Will the alarm ring if I close the browser tab?

No. Keep the tab open and your screen on. The alarm runs in the browser tab so it needs to remain active.

Can I run the countdown timer in full screen?

Yes. Click the expand icon in the top right corner of the timer section to enter full-screen mode on any monitor or projector.

Is the stopwatch accurate over long durations?

Yes. The stopwatch uses requestAnimationFrame against the system timestamp rather than counting intervals, ensuring zero drift over any duration.

How do I convert time between time zones?

Go to the Time Zone Converter tool, enter your time, select your source and target time zones, and click Convert. The tool automatically handles Daylight Saving Time rules.

How is my exact age calculated?

Enter your date of birth and an optional target date. The calculator breaks down your age into exact years, months, and days accounting for leap years and varying month lengths.

Can the hours calculator handle overnight shifts?

Yes. If your end time is earlier than your start time, the calculator automatically adds 24 hours to correctly calculate overnight or midnight-crossing shifts.

How many cities can I add to the world clock?

You can add any city or time zone from the full IANA timezone database — over 400 locations worldwide. Search by city name or region in the input field.

Time Zone Converter — Free & Instant

Time Zone Converter — Convert Time Between Any Two Time Zones

Stop manually calculating time zone differences. The OnlineTimeZone converter uses the browser's native ICU timezone dataset to accurately convert any time between any two of the 400+ IANA time zones. Daylight Saving Time rules for all regions are applied automatically — no need to remember which countries currently observe DST or what their offset is.

Frequently Asked Questions — Time Zone Converter

How do I convert a time from one time zone to another?

Enter the time you want to convert in the "Time in Source Zone" field, select your source time zone from the first dropdown (it auto-detects your local zone by default), then choose your target time zone from the second dropdown and click Convert. The result shows the equivalent time in your target zone, fully accounting for the UTC offset difference and any applicable Daylight Saving Time rules.

Does the time zone converter automatically handle Daylight Saving Time?

Yes, completely automatically. The converter uses the Intl.DateTimeFormat API with the full IANA timezone database, which contains all historical and current Daylight Saving Time rules for every country and region. Whether you are converting a time in summer (when many regions observe DST) or winter (when most regions revert to standard time), the correct offset is applied without any manual input from you.

What time zones are available in the converter?

All 400+ time zones in the IANA (Internet Assigned Numbers Authority) timezone database are available. This includes every country, territory, and historical time zone on Earth — from America/New_York and Europe/London to Asia/Kolkata, Pacific/Auckland, and even unusual zones like Asia/Kathmandu (UTC+5:45) and Asia/Kolkata (UTC+5:30). Simply search or scroll through the dropdown to find your zone.

How do I find the best meeting time for participants in different countries?

Use the converter to check what your proposed meeting time looks like in each participant's time zone. For example, if you want to schedule at 10:00 AM New York time, convert it to London (typically 3:00 PM GMT) and Mumbai (typically 8:30 PM IST) to check if those times are reasonable working hours. For a visual overview of multiple cities simultaneously, use the World Clock tool to see all times side by side.

What is the difference between UTC, GMT, and standard time zones?

UTC (Coordinated Universal Time) is the global time standard with no offset — it is the baseline from which all other time zones are measured. GMT (Greenwich Mean Time) is historically the same as UTC and used interchangeably in everyday language. Standard time zones like EST (Eastern Standard Time) or IST (Indian Standard Time) are defined by their fixed offset from UTC — for example, IST is UTC+5:30. The IANA database used by this converter uses named zones (like Asia/Kolkata) rather than abbreviations, because abbreviations like "CST" can refer to multiple different zones worldwide.

Global Time Zone Converter Tool