Timezone Converter

Working across timezones is one of the most common challenges for remote teams, international travelers, and global businesses. Whether you're scheduling a meeting with colleagues in Tokyo, coordinating a product launch across London, New York, and Sydney, or simply trying to figure out if it's too late to call a friend abroad, a reliable timezone converter saves time and prevents costly scheduling mistakes.

Our timezone converter uses the IANA timezone database, the same standard used by operating systems, programming languages, and global infrastructure. This ensures accurate, up-to-date timezone data including daylight saving time (DST) transitions, historical timezone changes, and regional variations.

Compare multiple timezones at a glance

Unlike simple clock widgets that show one timezone at a time, our converter lets you add as many timezones as you need and compare them side by side. Each timezone card displays the current local time with second-level precision, the date, and the UTC offset. This makes it easy to find overlapping working hours, identify the best time for a call, or simply stay aware of what time it is for people you care about around the world.

12-hour and 24-hour time formats

Different regions use different time conventions. The United States, Canada, Australia, and a handful of other countries primarily use the 12-hour format with AM/PM indicators. Most of Europe, Asia, Africa, and Latin America use the 24-hour format. Our converter supports both formats with a simple toggle, so you can view times in whichever convention feels most natural to you or your audience.

Free, private, and works offline

This timezone converter runs entirely in your browser. No data is sent to any server. No account is required. No cookies are set. Once the page loads, it works completely offline using your browser's built-in timezone database and your device's system clock. Your timezone selections stay private and disappear when you close the tab.

Whether you're a digital nomad coordinating across continents, a project manager scheduling sprints with a distributed team, or a trader tracking market hours in New York, London, and Hong Kong, this tool gives you the time information you need instantly, without friction.

Understanding UTC and GMT

UTC (Coordinated Universal Time) and GMT (Greenwich Mean Time) are often used interchangeably, but they are not the same thing. GMT is a timezone originally based on the mean solar time observed at the Royal Observatory in Greenwich, England. It served as the world's time reference standard for over a century. UTC, on the other hand, is a modern time standard maintained by a network of atomic clocks distributed around the world, coordinated by the International Bureau of Weights and Measures (BIPM) in Paris.

For most everyday purposes, UTC and GMT show the same time. The difference is technical: UTC is based on International Atomic Time (TAI) with occasional leap seconds added to keep it aligned with Earth's rotation, while GMT is defined by astronomical observation. UTC is the standard used in aviation, computing, scientific research, weather forecasting, and international communications. When you see a timezone described as UTC+5 or UTC-8, it means the local time is 5 hours ahead or 8 hours behind Coordinated Universal Time.

How timezone offsets work

Every timezone in the world is defined as an offset from UTC. Positive offsets (UTC+1, UTC+2, etc.) are east of the Prime Meridian and ahead of UTC. Negative offsets (UTC-1, UTC-5, etc.) are west of the Prime Meridian and behind UTC. For example, Tokyo operates at UTC+9, meaning when it's 12:00 noon UTC, it's 9:00 PM in Tokyo. New York during Eastern Standard Time is UTC-5, so the same UTC noon would be 7:00 AM in New York.

Not all offsets are whole hours. India Standard Time (IST) is UTC+5:30, Nepal Standard Time is UTC+5:45, and the Chatham Islands in New Zealand use UTC+12:45. Australia has several unusual offsets including UTC+8:45 for the area around Eucla in Western Australia and UTC+9:30 for the Northern Territory and South Australia. These half-hour and quarter-hour offsets exist for historical, geographical, or political reasons and are fully supported by our converter.

Daylight Saving Time (DST) explained

Daylight Saving Time is the practice of advancing clocks by one hour during warmer months so that evenings have more daylight. In the Northern Hemisphere, clocks typically "spring forward" in March or April and "fall back" in October or November. The Southern Hemisphere follows the opposite schedule. During DST, a timezone's UTC offset changes: for example, the US Eastern timezone shifts from UTC-5 (EST) to UTC-4 (EDT).

Not all countries or regions observe DST. Most of Africa, Asia, and South America do not use it. Within countries that do observe DST, there can be exceptions: Arizona in the United States does not observe DST (except the Navajo Nation), and Queensland in Australia stays on standard time year-round. Several countries have recently abolished DST, including Russia (2014), Turkey (2016), and Morocco (2018, switching to permanent DST). Our converter automatically handles all of these variations because it relies on the IANA timezone database, which tracks DST rules for every region.

The IANA timezone database

The IANA timezone database, also known as the tz database or Olson database (named after its original creator Arthur David Olson), is the most widely used timezone reference in the world. It is maintained by a community of volunteers under the coordination of ICANN (the Internet Corporation for Assigned Names and Numbers) and is updated multiple times per year to reflect changes in timezone rules made by governments worldwide.

Timezones in the IANA database follow an "Area/City" naming convention, such as "America/New_York", "Europe/London", "Asia/Tokyo", or "Australia/Sydney". The city chosen is typically the largest or most well-known city in the timezone region. This naming system avoids ambiguous abbreviations and captures historical timezone data, including past changes to UTC offsets and DST rules. Every major operating system (Windows, macOS, Linux, iOS, Android) and every modern web browser includes a copy of this database, which is what powers our converter through the JavaScript Intl API.

Common use cases for timezone conversion

Scheduling international meetings. When your team spans multiple timezones, finding a meeting time that works for everyone requires comparing local times across all participants. Add each person's timezone and visually identify overlapping business hours.

Remote team coordination. Distributed teams need to know when colleagues are online, when their workday starts and ends, and when handoffs happen. Keeping a set of team timezones visible helps avoid messaging people at 3 AM their time.

Travel planning. Before you land in a new city, check the time difference so you can plan your arrival, adjust your sleep schedule, and know when to contact people back home. This is especially useful for multi-city trips that cross several timezone boundaries.

Tracking global market hours. Stock exchanges around the world operate on their local business hours. The New York Stock Exchange (NYSE) opens at 9:30 AM ET, the London Stock Exchange (LSE) at 8:00 AM GMT, and the Tokyo Stock Exchange (TSE) at 9:00 AM JST. Traders and investors use timezone converters to know exactly when each market opens and closes relative to their own local time.

International event coordination. Whether it's a global product launch, a live-streamed webinar, an international sports event, or a gaming tournament, organizers need to communicate event times clearly across all timezones. Converting a single event time to multiple local times prevents confusion and ensures maximum participation.

Major world timezones reference

North America: Eastern Time (ET) covers New York, Toronto, and Miami at UTC-5/UTC-4. Central Time (CT) covers Chicago, Houston, and Mexico City at UTC-6/UTC-5. Mountain Time (MT) covers Denver and Phoenix at UTC-7/UTC-6. Pacific Time (PT) covers Los Angeles, San Francisco, and Vancouver at UTC-8/UTC-7. Alaska Time (AKT) is at UTC-9/UTC-8, and Hawaii-Aleutian Time (HAT) is at UTC-10.

Europe: Greenwich Mean Time/British Summer Time (GMT/BST) covers London and Dublin at UTC+0/UTC+1. Central European Time (CET/CEST) covers Paris, Berlin, Rome, and Madrid at UTC+1/UTC+2. Eastern European Time (EET/EEST) covers Athens, Helsinki, and Bucharest at UTC+2/UTC+3. Moscow Standard Time (MSK) is at UTC+3 year-round.

Asia: India Standard Time (IST) covers the entire country at UTC+5:30. China Standard Time (CST) covers all of mainland China at UTC+8 despite the country spanning five geographical timezone widths. Japan Standard Time (JST) is at UTC+9. Korea Standard Time (KST) is also at UTC+9. Southeast Asian countries range from UTC+6 (Bangladesh) to UTC+8 (Singapore, Malaysia, Philippines).

Oceania: Australian Eastern Standard Time (AEST/AEDT) covers Sydney and Melbourne at UTC+10/UTC+11. Australian Central Standard Time (ACST/ACDT) covers Adelaide at UTC+9:30/UTC+10:30. New Zealand Standard Time (NZST/NZDT) is at UTC+12/UTC+13.

A note on abbreviations: Timezone abbreviations can be ambiguous. "IST" can refer to India Standard Time (UTC+5:30), Irish Standard Time (UTC+1), or Israel Standard Time (UTC+2). "CST" can mean Central Standard Time (UTC-6) in the US, China Standard Time (UTC+8), or Cuba Standard Time (UTC-5). This is why the IANA database uses unambiguous Area/City identifiers instead of abbreviations, and why our tool displays the full timezone name alongside the UTC offset.

Tips for working across timezones

Find the overlap window. For most international teams, there are only a few hours each day when everyone is awake during reasonable working hours. Identify this window and use it for synchronous communication like meetings and calls. Protect it from non-essential interruptions.

Use UTC as a shared reference. When communicating times across multiple timezones, stating the time in UTC alongside local time eliminates ambiguity. For example, "The deployment is scheduled for 18:00 UTC (2:00 PM ET / 7:00 PM CET)" is clear to everyone regardless of where they are.

Be aware of DST transitions. Twice a year (or more, depending on the timezones involved), the time difference between regions changes. A meeting that was convenient for everyone can suddenly fall outside someone's working hours after a DST shift. Check your timezone converter around March and November to verify that scheduled recurring events still work.

Respect the time difference. Just because a message can be sent at any time does not mean it should be. Consider using scheduled send features for emails and marking non-urgent messages appropriately. A culture of asynchronous communication reduces pressure on people in disadvantageous timezones.

Keep a persistent timezone display. Whether you use this converter, a desktop widget, or a phone app, keeping frequently referenced timezones visible at all times builds natural awareness of what time it is for the people you work with. Over time, you'll develop an intuitive sense of the offsets without needing to look them up.