Time Zones Converter
Enter a time and select your source and destination time zones. The converter calculates the equivalent time at the destination, shows the offset difference, the UTC equivalent, and whether the result falls on the same day, the day before, or the day after. All 38 standard UTC offsets from UTC-12 to UTC+14 are supported, including half-hour and quarter-hour offsets such as India (UTC+05:30), Iran (UTC+03:30), and Nepal (UTC+05:45).
How time zone conversion works
Every time zone is defined by its offset from Coordinated Universal Time (UTC), the successor to Greenwich Mean Time (GMT). To convert a time from one zone to another, the process has three steps: first subtract the source UTC offset to get the UTC equivalent, then add the destination UTC offset to get the local time there. If the resulting hour is below 0 or above 23, the day rolls backward or forward by one or more days. For example, 09:00 New York (UTC-05:00) converted to London (UTC+00:00) gives 09:00 + 5h = 14:00 the same day. Converted to Tokyo (UTC+09:00) it gives 09:00 + 14h = 23:00 the same day. But 23:00 New York to Tokyo (09:00 + 14h = 09:00 next day) crosses midnight.
Standard offsets vs. daylight saving time
This converter uses standard (non-DST) UTC offsets so results are deterministic regardless of the time of year. In practice, many countries observe daylight saving time (DST) for part of the year, temporarily shifting clocks forward by one hour. The United States moves from Eastern Standard Time (UTC-05:00) to Eastern Daylight Time (UTC-04:00) from the second Sunday in March to the first Sunday in November. The European Union shifts all member zones by one hour on the last Sunday in March and reverts on the last Sunday in October. Countries near the equator, most of Asia, and Africa generally do not observe DST. To account for DST, add or subtract one hour from the offset shown here during the applicable months.
Non-standard half-hour and quarter-hour offsets
Most time zones sit on whole-hour offsets from UTC, but several countries use half-hour or even quarter-hour offsets for historical or geographic reasons. India Standard Time is UTC+05:30, Nepal Time is UTC+05:45 (the only quarter-hour offset currently in regular use), Iran Standard Time is UTC+03:30, and Australian Central Standard Time is UTC+09:30. Afghanistan uses UTC+04:30. This converter supports all 38 recognised offsets from UTC-12:00 (Baker Island) to UTC+14:00 (Kiritimati, Christmas Island), which is the widest east-to-west span of any pair of time zones on Earth.
Scheduling across time zones
When scheduling international meetings or calls, a useful rule of thumb is to find an overlap in normal business hours (roughly 09:00 to 17:00 local time) for all participants. The offset difference between New York (UTC-05:00) and London (UTC+00:00) is 5 hours in winter and 4 hours in summer due to DST. Between New York and Tokyo (UTC+09:00) the gap is 14 hours in winter, meaning a 09:00 meeting in New York corresponds to 23:00 in Tokyo, which is outside business hours. The far end of the same-day band for these two cities is roughly 08:00 New York = 22:00 Tokyo, so early morning on the US East Coast is the only practical overlap. Always check whether DST is active in either location when planning across the Northern Hemisphere spring and autumn transitions.
Major world time zones and UTC offsets
| Region / City | Time Zone Name | UTC Offset |
|---|---|---|
| Honolulu | Hawaii Standard Time | UTC-10:00 |
| Anchorage | Alaska Standard Time | UTC-09:00 |
| Los Angeles, Seattle | Pacific Standard Time | UTC-08:00 |
| Denver, Phoenix | Mountain Standard Time | UTC-07:00 |
| Chicago, Mexico City | Central Standard Time | UTC-06:00 |
| New York, Miami, Toronto | Eastern Standard Time | UTC-05:00 |
| Halifax, Caracas | Atlantic Standard Time | UTC-04:00 |
| St. Johns | Newfoundland Standard Time | UTC-03:30 |
| Buenos Aires, Sao Paulo | South America Time | UTC-03:00 |
| London, Reykjavik | Greenwich Mean Time | UTC+00:00 |
| Paris, Berlin, Rome | Central European Time | UTC+01:00 |
| Cairo, Athens, Helsinki | Eastern European Time | UTC+02:00 |
| Moscow, Nairobi | Moscow / East Africa Time | UTC+03:00 |
| Tehran | Iran Standard Time | UTC+03:30 |
| Dubai, Abu Dhabi | Gulf Standard Time | UTC+04:00 |
| Kabul | Afghanistan Time | UTC+04:30 |
| Karachi, Tashkent | Pakistan Standard Time | UTC+05:00 |
| Mumbai, Kolkata, Delhi | India Standard Time | UTC+05:30 |
| Kathmandu | Nepal Time | UTC+05:45 |
| Dhaka, Almaty | Bangladesh Standard Time | UTC+06:00 |
| Yangon | Myanmar Time | UTC+06:30 |
| Bangkok, Jakarta, Hanoi | Indochina Time | UTC+07:00 |
| Beijing, Singapore, Perth | China Standard Time | UTC+08:00 |
| Tokyo, Seoul | Japan / Korea Standard Time | UTC+09:00 |
| Adelaide | Australian Central Standard Time | UTC+09:30 |
| Sydney, Melbourne, Brisbane | Australian Eastern Standard Time | UTC+10:00 |
| Auckland | New Zealand Standard Time | UTC+12:00 |
Standard (non-DST) UTC offsets for major cities and regions. Daylight saving time adds +1 hour in applicable regions.
Frequently asked questions
How do I convert a time between time zones?
Subtract the source UTC offset from your local time to get the UTC equivalent, then add the destination UTC offset. For instance, 15:00 in Paris (UTC+01:00) minus 1 hour equals 14:00 UTC. Adding 9 hours for Japan (UTC+09:00) gives 23:00 Tokyo time the same day. This calculator does both steps automatically.
Does this converter account for daylight saving time?
No - it uses fixed standard UTC offsets throughout the year. Daylight saving time shifts the effective offset by one hour in regions that observe it (most of North America, Europe, and parts of Australia). During DST, add one hour to the standard offset for that region before converting. For example, New York becomes UTC-04:00 instead of UTC-05:00 during Eastern Daylight Time.
What does "next day" or "previous day" mean in the result?
When the converted time crosses midnight, the result falls on a different calendar day than the source. "Next day (+1)" means the destination time is on the day after the source date; "Previous day (-1)" means it is on the day before. This happens when the UTC equivalent of your source time plus the destination offset goes above 24 or below 0.
Why does India have a half-hour offset (UTC+05:30)?
India adopted UTC+05:30 in 1906 as a compromise between the two time zones that would have otherwise split the country geographically. A whole-hour offset would have placed sunrise or sunset at inconvenient times for a large part of the population. Nepal uses an even more unusual UTC+05:45, chosen to differ from India by 15 minutes as a mark of national distinction.
What is the difference between UTC, GMT, and a time zone offset?
Coordinated Universal Time (UTC) is the primary time standard by which the world regulates clocks. Greenwich Mean Time (GMT) is the mean solar time at the Royal Observatory in Greenwich, London, and is numerically equal to UTC at any given moment for practical purposes. A time zone offset is the number of hours (and sometimes minutes) by which a region differs from UTC. UTC+05:30 means a clock showing that time is 5 hours and 30 minutes ahead of UTC.
Which time zones span more than one calendar day from each other?
The maximum offset difference between any two time zones is 26 hours - from UTC-12:00 (Baker Island) to UTC+14:00 (Kiritimati). This means Monday 00:00 in Kiritimati corresponds to Saturday 22:00 in Baker Island, a full two calendar days apart.