Time Zone Converter - Compare 23 World Zones

Coordinating across time zones is a daily reality for anyone who works with international teams, schedules calls with clients abroad, books flights across continents, or simply wants to know what time it is when a loved one in another country wakes up.

Getting time zone math wrong means missed meetings, early morning wake-up calls, and frustrated colleagues.

This time zone converter lets you convert any time between any two time zones in the world. It supports all IANA (Internet Assigned Numbers Authority) time zone identifiers, which are the standard used by operating systems, programming languages, and scheduling software worldwide. The converter automatically accounts for daylight saving time (DST) transitions, so you get the correct time even during the weeks when different countries spring forward or fall back on different dates.

Select your source and destination time zones, enter a date and time, and get an instant result. You can also compare multiple time zones simultaneously to find the best meeting window for participants spread across the globe. No more mental arithmetic, no more accidental off-by-one-hour errors during DST transitions.

How Time Zones Work

The Earth is divided into 24 standard time zones, each nominally covering 15 degrees of longitude (360 degrees divided by 24 hours). In practice, time zone boundaries follow political borders rather than neat meridian lines, which is why the world time zone map looks jagged and irregular.

Coordinated Universal Time (UTC) is the global reference standard from which all time zones are measured. UTC replaced Greenwich Mean Time (GMT) as the international standard in 1972 and is maintained by atomic clocks. While UTC and GMT are functionally the same for civilian purposes (both refer to the time at the prime meridian in Greenwich, London), UTC is the technically correct reference for time zone offsets.

Time zones are expressed as offsets from UTC. Eastern Standard Time in the United States is UTC-5, meaning it is 5 hours behind UTC. Central European Time is UTC+1. India Standard Time is UTC+5:30. Some time zones use half-hour or even quarter-hour offsets: India is UTC+5:30, Nepal is UTC+5:45, and the Chatham Islands of New Zealand use UTC+12:45.

IANA Time Zone Database

The IANA Time Zone Database (also called the tz database or Olson database) is the authoritative source of time zone data used by virtually every computer, phone, and server in the world. Rather than using abbreviations like "EST" or "PST" (which can be ambiguous), the IANA database uses location-based identifiers in the format "Continent/City."

Examples of IANA identifiers:

America/New_York (Eastern Time, US)
America/Los_Angeles (Pacific Time, US)
America/Chicago (Central Time, US)
Europe/London (UK time)
Europe/Paris (Central European Time)
Asia/Tokyo (Japan Standard Time)
Asia/Kolkata (India Standard Time)
Australia/Sydney (Australian Eastern Time)
Pacific/Auckland (New Zealand Time)

The advantage of IANA identifiers over abbreviations is that they are unambiguous. "CST" could mean Central Standard Time (UTC-6), China Standard Time (UTC+8), or Cuba Standard Time (UTC-5). "America/Chicago" can only mean one thing. This converter uses IANA identifiers for maximum accuracy.

Daylight Saving Time Complications

Daylight saving time (DST) is the practice of moving clocks forward by one hour in spring and back by one hour in autumn. It is the single biggest source of time zone conversion errors because different countries implement DST on different dates, some countries do not observe it at all, and the rules change periodically.

Countries that observe DST include the United States, Canada, most of Europe, parts of Australia, New Zealand, and scattered other nations. In the Northern Hemisphere, clocks typically spring forward in March and fall back in November. In the Southern Hemisphere, the dates are reversed (spring forward in September/October, fall back in March/April).

Countries that do not observe DST include most of Asia (China, Japan, India, South Korea), most of Africa, and most of South America. Russia abolished DST in 2011. Arizona (except the Navajo Nation) does not observe DST within the United States. Hawaii also does not observe DST.

The transition gap problem. The US springs forward on the second Sunday of March, while the EU springs forward on the last Sunday of March. During the roughly two-week gap between these dates, the time difference between New York and London is 4 hours instead of the usual 5 hours. A meeting that is normally at 2 PM New York / 7 PM London suddenly becomes 2 PM New York / 6 PM London. This converter handles these transitions automatically by referencing the IANA database for the specific date you enter.

Common Time Zone Conversions

US to UK. Eastern Time to London is normally -5 hours (EST) or -4 hours during summer (EDT to BST). When both countries are on standard time or both on daylight time, the difference is 5 hours. During the DST transition gap weeks, it temporarily becomes 4 hours.

US to Europe. Eastern Time to Central European Time (Paris, Berlin, Madrid) is normally -6 hours (EST to CET) or -6 hours during summer (EDT to CEST). The consistent 6-hour difference holds when both regions are on the same DST schedule.

US to India. Eastern Time to India Standard Time (IST) is -10.5 hours during EST or -9.5 hours during EDT. India does not observe DST, so the offset changes when the US shifts.

US to Japan. Eastern Time to Japan Standard Time (JST) is -14 hours during EST or -13 hours during EDT. Japan does not observe DST.

US to Australia. Eastern Time to Australian Eastern Time (Sydney) varies dramatically: from -14 hours to -16 hours depending on which country is currently observing DST and which is not, since their seasons are opposite.

Scheduling Across Multiple Time Zones

Finding a meeting time that works for participants in multiple time zones is one of the most common and frustrating scheduling challenges. Here are practical strategies.

Identify the overlap window. For any group of time zones, there is typically a range of hours where all participants are within reasonable working hours (roughly 8 AM to 8 PM local time). For US East Coast and Western Europe, the overlap is approximately 9 AM to 12 PM Eastern (2 PM to 5 PM in London, 3 PM to 6 PM in Paris). For US West Coast and East Asia, there is almost no overlap during normal business hours, making early morning or late evening calls necessary for one side.

Rotate the inconvenience. For recurring meetings across time zones with no good overlap, rotate the meeting time so the burden of early morning or late evening calls is shared among all participants rather than always falling on the same group.

Use the UTC anchor. When scheduling for a large, international audience, publish the time in UTC and let each participant convert to their local time. This avoids ambiguity and DST confusion. For example, "meeting at 14:00 UTC" is clear to everyone regardless of their time zone.

Avoid scheduling during DST transitions. The two weeks around DST transitions (March and November in the Northern Hemisphere) are particularly error-prone. If possible, avoid scheduling new international meetings during these periods, or double-check all times using this converter with the specific date.

The International Date Line

The International Date Line (IDL) runs roughly along the 180-degree meridian in the Pacific Ocean, with deviations to keep island nations and territories in the same day as their economic partners. When you cross the date line heading westward, you skip ahead one day. Heading eastward, you go back one day.

This creates the counterintuitive situation where it can be two different calendar dates at the same moment in different parts of the world. When it is 10 PM Monday in New York (UTC-5), it is already 2 PM Tuesday in Sydney (UTC+11). When converting times that cross the date line, always pay attention to the date as well as the time.

Some Pacific island nations have offsets greater than UTC+12. Kiribati’s Line Islands use UTC+14, making them the first place on Earth to see each new day. When it is midnight January 1 in the Line Islands, it is still 10 AM December 31 in UTC, meaning the world spans two calendar days for a brief period.

Time Zone Abbreviations Reference

While IANA identifiers are preferred for precision, abbreviations are commonly used in everyday communication. Here are the major ones and their UTC offsets.

Americas:

EST/EDT: UTC-5 / UTC-4 (Eastern)
CST/CDT: UTC-6 / UTC-5 (Central)
MST/MDT: UTC-7 / UTC-6 (Mountain)
PST/PDT: UTC-8 / UTC-7 (Pacific)
AKST/AKDT: UTC-9 / UTC-8 (Alaska)
HST: UTC-10 (Hawaii, no DST)

Europe:

GMT/BST: UTC+0 / UTC+1 (UK)
CET/CEST: UTC+1 / UTC+2 (Central Europe)
EET/EEST: UTC+2 / UTC+3 (Eastern Europe)

Asia-Pacific:

IST: UTC+5:30 (India)
CST: UTC+8 (China, no DST)
JST: UTC+9 (Japan, no DST)
KST: UTC+9 (South Korea, no DST)
AEST/AEDT: UTC+10 / UTC+11 (Australia Eastern)
NZST/NZDT: UTC+12 / UTC+13 (New Zealand)

Frequently Asked Questions

What is UTC and how does it differ from GMT?

UTC (Coordinated Universal Time) is the global time standard from which all time zones are calculated. GMT (Greenwich Mean Time) refers to the mean solar time at the Royal Observatory in Greenwich, London. For practical everyday purposes they are identical, but UTC is the technically correct reference used by international standards.

How do I find the time difference between two cities?

Select both cities in this converter and it will show the current time difference, accounting for daylight saving time if applicable. The difference may change during DST transitions, so always check with the specific date if scheduling weeks in advance.

Does this converter account for daylight saving time?

Yes. This converter uses the IANA Time Zone Database, which includes all historical and current DST rules for every time zone. Enter the specific date and time you need to convert, and the tool automatically applies the correct DST offset.

Why do some time zones have half-hour offsets?

Several countries chose half-hour offsets to better align their clock time with solar noon. India uses UTC+5:30, Iran uses UTC+3:30, and Afghanistan uses UTC+4:30. Nepal uses UTC+5:45, and the Chatham Islands of New Zealand use UTC+12:45. These non-standard offsets reflect geographic and political decisions.

What is the International Date Line?

The International Date Line is an imaginary line running through the Pacific Ocean roughly along the 180-degree meridian. When crossing it westward, you advance one calendar day. Crossing eastward, you go back one day. It ensures that the world’s time zones create a logical sequence of dates.

How many time zones are there in the world?

There are more than 24 unique time zones because of half-hour and quarter-hour offsets. The IANA Time Zone Database defines over 400 time zone identifiers to account for different regions, DST rules, and historical changes. The UTC offsets in current use range from UTC-12 to UTC+14.

Why does Arizona not observe daylight saving time?

Arizona opted out of DST in 1968, primarily because the extra hour of evening sunlight during summer was undesirable in the extreme desert heat. During the summer months, Arizona is on the same time as Pacific Daylight Time. The Navajo Nation within Arizona does observe DST.

Time zone data based on the IANA Time Zone Database. DST rules current as of: March 2026