Time Zone Converter
Convert a specific clock time between any two UTC offsets — enter the source time plus the two offsets and get the destination local time, with automatic
Time Zone Converter
Calculator
Adjust values & calculateEnter your values below. Every result is computed in your browser — no data is sent to any server.
Formula: Target Time = Source Time + (To_Offset - From_Offset)
Worked example — 19:30 GMT
Formula
Target Time = Source Time + (To_Offset - From_Offset)
UTC offsets: EST=-5, CST=-6, PST=-8, GMT=0, CET=+1, IST=+5.5, JST=+9, AEST=+10.
Worked Examples
Example 1: NYC to London
Problem:14:30 EST (UTC-5) to GMT (UTC+0)
Solution:14:30 + 5 hours = 19:30
Result:19:30 GMT
Example 2: Crossing midnight into the next day
Problem:Convert 22:00 in Los Angeles (PST, UTC-8) to Tokyo (JST, UTC+9)
Solution:Offset difference = 9 - (-8) = 17 hours 22:00 + 17:00 = 39:00 → 39:00 - 24:00 = 15:00 the next day
Result:15:00 JST (next day)
Frequently Asked Questions
How do UTC offsets relate to lines of longitude?
The Earth turns 360 degrees in 24 hours, so each hour of offset corresponds to roughly 15 degrees of longitude. An idealised zone would be a 15-degree band centred on a meridian, but real zone boundaries follow national and provincial borders instead, which is why some countries far from the Greenwich meridian keep a single offset. China spans about 60 degrees of longitude yet runs entirely on UTC+8, so solar noon in its far west falls well after clock noon.
Which time zones use half-hour or quarter-hour offsets?
Several time zones use non-standard offsets. India Standard Time (IST) is UTC+5:30. Nepal is UTC+5:45. Iran is UTC+3:30 year-round. Australia has states spanning UTC+8, UTC+9:30 and UTC+10, with South Australia moving to UTC+10:30 in summer. These fractional offsets arose historically to balance geographic and political boundaries without adopting a neighboring country's full-hour time.
What is the International Date Line and how does it affect time conversions?
The International Date Line runs roughly along the 180° meridian in the Pacific Ocean. Crossing it eastward (traveling from Asia to Americas) moves you back one calendar day; crossing westward moves you forward one day. Time Zone Converter handles day changes automatically (showing 'next day' or 'previous day' in the output). Kiribati and Samoa (which Tokelau followed in 2011) are examples of nations near the date line that have shifted to the western side for economic alignment with Asia-Pacific partners.
How should I handle scheduling across multiple time zones for a meeting?
Choose a time that falls within business hours (9am-5pm) for all participants where possible. Tools like World Time Buddy or Time Zone Converter can help identify overlap windows. For globally distributed teams, rotating meeting times so the inconvenient hour is shared fairly shows consideration. Always confirm the time zone in the meeting invitation using both the local time AND the UTC offset to prevent ambiguity during DST transitions.
What UTC offset should I enter for a specific abbreviation like EST or CET?
Common standard-time offsets are EST=-5, CST=-6, MST=-7, PST=-8, GMT/UTC=0, CET=+1, EET=+2, MSK=+3, GST(Dubai)=+4, IST(India)=+5.5, ICT(Bangkok)=+7, SGT/CST(China)=+8, JST(Japan)=+9, AEST(Sydney standard)=+10. During daylight saving time, add 1 hour to zones that observe it (e.g., EST becomes EDT at -4, CET becomes CEST at +2). Always double-check whether the date you're converting for falls inside the DST window for both locations.
Does Time Zone Converter account for daylight saving time automatically?
No — because DST start and end dates vary by country and change some years by legislation, Time Zone Converter asks you to enter the UTC offset directly rather than a named zone, so you retain full control. If either location observes DST on the date you're converting for, add 1 to that location's standard offset before entering it (e.g., use -4 instead of -5 for US Eastern in summer). This avoids the common error of using a named zone abbreviation that silently shifts meaning twice a year.
What is the difference between UTC and GMT?
GMT is a time zone based on mean solar time at the Greenwich meridian, still used as civil time in the UK during winter. UTC is a coordinated atomic time scale kept within 0.9 seconds of solar time by occasional leap seconds, and it is the reference all offsets are measured from. For everyday conversion they are interchangeable at offset 0, so entering 0 works for either. Aviation, computing and broadcasting standards specify UTC because it is defined by atomic clocks rather than Earth rotation.
Why are time zone abbreviations like CST and IST ambiguous?
Abbreviations are not standardised and several are reused across continents. CST can mean Central Standard Time at UTC-6 in North America or China Standard Time at UTC+8. IST can mean India Standard Time at UTC+5:30 or Irish Standard Time at UTC+1. This is exactly why the calculator asks for a numeric UTC offset rather than a label: the offset is unambiguous. When scheduling with someone abroad, confirm the offset or an IANA zone identifier such as America/Chicago rather than the letters.
How do I convert a time that falls during a daylight saving changeover?
Changeovers create one hour that does not exist and one that occurs twice. When clocks spring forward, local times in the skipped hour are invalid, so a meeting set then has no real instant. When clocks fall back, the repeated hour is ambiguous unless you state which offset applies. The safe method is to convert both sides through UTC using the offset in force at that exact moment, entering the pre-change offset for times before the switch and the post-change offset after it.
Why do southern hemisphere conversions shift in the opposite direction from northern ones?
Seasons are reversed south of the equator, so places such as parts of Australia, New Zealand and Chile move their clocks forward in the southern spring — New Zealand in late September, Australia in early October, Chile in early September — and back around April, while North America and Europe do the reverse. For a few weeks each spring and autumn the two hemispheres are shifting in opposite directions, which can swing the gap between two cities by two hours within a month. Recheck both UTC offsets around those windows rather than reusing an offset difference you calculated earlier in the year.
References
Reviewed for accuracy by Daniel Agrici, Founder & Lead Developer · Editorial policy
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