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Time Zone Converter
Convert times accurately across the world — DST-aware
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Live Clock Mode
Auto-updates every second
S Source Time
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Target Time Zones
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Enter a date, time, and time zones to convert
Results will appear here
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Source
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UTC Reference
UTC+0:00
⚡ DST Information
How the conversion handles offsets and daylight saving
The tool combines the date and time you enter with the source zone to produce a single instant in time, expressed internally in UTC. That instant is then formatted separately for each target zone. Because everything pivots through one absolute moment, the result stays correct regardless of how many zones you compare or how odd their offsets are.
Formatting uses the Intl.DateTimeFormat interface built into your browser, which draws on the IANA time zone database. That database holds not just the current offset for each zone but the rules and historical changes, so the tool applies daylight saving automatically for the date you chose rather than assuming today's offset. Entering a date in July gives British Summer Time for London and Eastern Daylight Time for New York; the same entry in January gives GMT and EST.
This matters because the gap between two cities is not constant. London and New York are usually five hours apart, but for about two weeks each year the two regions switch at different dates and the gap becomes four hours.
Formatting uses the Intl.DateTimeFormat interface built into your browser, which draws on the IANA time zone database. That database holds not just the current offset for each zone but the rules and historical changes, so the tool applies daylight saving automatically for the date you chose rather than assuming today's offset. Entering a date in July gives British Summer Time for London and Eastern Daylight Time for New York; the same entry in January gives GMT and EST.
This matters because the gap between two cities is not constant. London and New York are usually five hours apart, but for about two weeks each year the two regions switch at different dates and the gap becomes four hours.
Worked example: a 09:00 London call in October
Set the source zone to Europe/London and enter 09:00 on a date in mid-October, before the UK clocks change. London is still on British Summer Time, one hour ahead of UTC, so the underlying instant is 08:00 UTC.
New York, on Eastern Daylight Time at UTC minus four, reads 04:00 the same morning, well outside business hours. Los Angeles, at UTC minus seven, reads 01:00, which is the middle of the night. Dubai, at UTC plus four, reads 12:00 midday. India, at UTC plus five and a half, reads 13:30, showing why half-hour offsets need care. Singapore and Shanghai, at UTC plus eight, read 16:00. Tokyo, at UTC plus nine, reads 17:00, and Sydney on daylight time at UTC plus eleven reads 19:00 that evening.
Only Dubai, India, Singapore, Shanghai and Tokyo sit inside a normal working day. Pushing the call to 14:00 London puts New York at 09:00 and Los Angeles at 06:00 while keeping Dubai at 17:00, which is the widest overlap available.
New York, on Eastern Daylight Time at UTC minus four, reads 04:00 the same morning, well outside business hours. Los Angeles, at UTC minus seven, reads 01:00, which is the middle of the night. Dubai, at UTC plus four, reads 12:00 midday. India, at UTC plus five and a half, reads 13:30, showing why half-hour offsets need care. Singapore and Shanghai, at UTC plus eight, read 16:00. Tokyo, at UTC plus nine, reads 17:00, and Sydney on daylight time at UTC plus eleven reads 19:00 that evening.
Only Dubai, India, Singapore, Shanghai and Tokyo sit inside a normal working day. Pushing the call to 14:00 London puts New York at 09:00 and Los Angeles at 06:00 while keeping Dubai at 17:00, which is the widest overlap available.
Scheduling across zones without slipping a day
Always read the local date alongside the local time. A Monday afternoon call in London can land on Tuesday morning in Sydney, and a Friday evening deadline in California is already Saturday in most of Asia. The date shown for each zone is the one that matters for anything contractual.
Daylight saving is the usual source of missed meetings. The northern and southern hemispheres shift in opposite directions, so the gap between London and Sydney swings between nine and eleven hours over the year, and the United States, Europe and Australia all change on different dates. A recurring meeting that works in March may be an hour out in April, so re-check fixed series after each transition. Several zones covered here, including India, Japan, the Gulf states and most of Africa, observe no daylight saving at all and stay on a single offset year-round.
Where precision is critical, confirm in writing using UTC alongside the local time, since zone abbreviations such as CST are ambiguous.
Daylight saving is the usual source of missed meetings. The northern and southern hemispheres shift in opposite directions, so the gap between London and Sydney swings between nine and eleven hours over the year, and the United States, Europe and Australia all change on different dates. A recurring meeting that works in March may be an hour out in April, so re-check fixed series after each transition. Several zones covered here, including India, Japan, the Gulf states and most of Africa, observe no daylight saving at all and stay on a single offset year-round.
Where precision is critical, confirm in writing using UTC alongside the local time, since zone abbreviations such as CST are ambiguous.
Frequently Asked Questions
Enter your proposed date and time in your own zone, add every participant's city as a target, and read the business-hours indicator on each row. Adjust the source time until the maximum number of rows fall inside working hours. Mid-morning in the westernmost zone usually produces the widest workable overlap.
Yes, automatically. It formats each zone using your browser's IANA time zone database, which contains the daylight saving rules and their historical changes. Because it applies the rules for the specific date you enter, a July conversion and a January conversion between the same two cities can differ by an hour.
India Standard Time is set at UTC plus 5:30, a compromise offset chosen so that a single zone could span a country wide enough to justify two. Nepal goes further at UTC plus 5:45, and Iran uses 3:30. Half and quarter-hour offsets are exactly why converting by mental arithmetic goes wrong.
Usually five hours, with New York behind London. The gap narrows to four hours for roughly two weeks in March and one week in late October or early November, because the United States and the United Kingdom change their clocks on different dates. Converting for a specific date avoids that trap.
Use city or IANA zone names. Abbreviations are ambiguous: CST means Central Standard Time in North America, China Standard Time in Asia and Cuba Standard Time in the Caribbean. EST also changes to EDT in summer, so a message sent in July specifying EST is technically wrong. Adding the UTC offset removes any doubt.