Time Zone Converter

About Time Zone Converter

Major World Time Zones

Abbreviation	Full Name	UTC Offset (standard)	Major Cities
UTC / GMT	Coordinated Universal Time	+0:00	London (winter), Reykjavik, Accra
EST / EDT	Eastern (US)	-5:00 / -4:00	New York, Toronto, Miami
CST / CDT	Central (US)	-6:00 / -5:00	Chicago, Houston, Mexico City
MST / MDT	Mountain (US)	-7:00 / -6:00	Denver, Phoenix (no DST), Calgary
PST / PDT	Pacific (US)	-8:00 / -7:00	Los Angeles, Seattle, Vancouver
CET / CEST	Central European	+1:00 / +2:00	Paris, Berlin, Rome, Madrid
EET / EEST	Eastern European	+2:00 / +3:00	Athens, Helsinki, Bucharest
IST	India Standard Time	+5:30	Mumbai, Delhi, Bangalore
CST (China)	China Standard Time	+8:00	Beijing, Shanghai, Hong Kong
JST	Japan Standard Time	+9:00	Tokyo, Osaka
AEST / AEDT	Australian Eastern	+10:00 / +11:00	Sydney, Melbourne, Brisbane (no DST)
NZST / NZDT	New Zealand	+12:00 / +13:00	Auckland, Wellington

Daylight Saving Time

Many time zones shift their clocks by one hour during summer months. The converter handles this automatically based on the selected date. DST rules vary significantly by country.

Region	DST Start	DST End	Shift
US / Canada (most)	Second Sunday in March	First Sunday in November	+1 hour
EU / UK	Last Sunday in March	Last Sunday in October	+1 hour
Australia (south)	First Sunday in October	First Sunday in April	+1 hour
Japan, China, India	No DST	No DST	N/A
Arizona (US)	No DST	No DST	N/A
Iceland	No DST	No DST	N/A

The EU voted in 2019 to end mandatory DST changes, but implementation has been delayed indefinitely. As of 2026, EU countries still observe DST. Always verify current rules for the specific location.

Common Time Differences

Route	Standard Offset	DST Offset	Notes
New York to London	+5 hours	+5 hours (both shift)	Gap can be +4 or +6 for 2-3 weeks during DST transitions
New York to Los Angeles	+3 hours (LA behind)	+3 hours (both shift)	Consistent year-round
London to Tokyo	+9 hours	+8 hours (UK shifts, Japan does not)	Changes when UK enters BST
New York to India	+10.5 hours	+9.5 hours	India does not observe DST
London to Sydney	+10 hours	Varies (+8 to +11)	Opposite hemispheres - both shift but in opposite directions

The trickiest period is the 2-3 weeks when one location has changed clocks but the other has not. For example, the US enters daylight saving time 2-3 weeks before Europe, so the New York-to-London gap temporarily shrinks from 5 to 4 hours.

UTC and Why It Matters

UTC (Coordinated Universal Time) is the global reference from which all time zones are defined as positive or negative offsets. It does not observe daylight saving time, making it a stable reference point. UTC replaced GMT as the international standard, though the two are nearly identical in practice (GMT is a time zone, UTC is a standard).

Use Case	Store Times As	Display Times As
Database records	UTC	User's local time zone
API timestamps	ISO 8601 with Z suffix (UTC)	Client converts to local
Server logs	UTC	UTC (for consistency across servers)
Scheduled events	UTC + user's IANA timezone	Local time with timezone abbreviation
Cron jobs	Server's timezone (often UTC)	N/A

The golden rule for developers: store in UTC, display in local. This avoids DST bugs and makes global applications work correctly.

Half-Hour and Quarter-Hour Time Zones

Not all time zones are whole-hour offsets from UTC. Several use 30-minute or even 45-minute offsets.

Time Zone	UTC Offset	Location
IST	+5:30	India
NPT	+5:45	Nepal
MMT	+6:30	Myanmar
ACST	+9:30	South Australia, Northern Territory
CHAST	+12:45	Chatham Islands (New Zealand)
NST	-3:30	Newfoundland (Canada)
MART	-9:30	Marquesas Islands (French Polynesia)

For working with Unix timestamps in code, the Unix Timestamp Converter pairs well with this tool. To calculate the number of days between two dates, use the Date Difference Calculator. All conversions use your browser's built-in timezone database.

How the Converter Reads the IANA Database

The converter asks the browser's built-in Intl.DateTimeFormat API to apply rules from the IANA tz database, the authoritative source for every timezone on Earth. The current release at the time of writing is 2026a, shipped in March 2026 by the IANA tz coordinator. Browsers refresh their internal copy of this database with each version update, so Chrome, Firefox, and Safari all resolve zone identifiers like Europe/London or America/Argentina/Cordoba to the correct offset for any date.

Worked example: setting the date to 15 July 2026 at 14:30 with source America/New_York and target Asia/Tokyo. On that date New York observes EDT (UTC-4) and Tokyo observes JST (UTC+9), so the converter reports 16 July 2026 at 03:30 JST - a 13-hour forward jump because Tokyo is on the other side of the date line from the UTC reference point.

Key DST Transition Dates for 2026

Most of Europe, North America, and southern Australia shift their clocks twice a year, but the exact dates rarely line up. The following transitions are the ones that break meeting schedules most often.

Region	Spring Shift (2026)	Autumn Shift (2026)	Local Transition Time
United States and Canada (most)	Sunday 8 March	Sunday 1 November	02:00 local
United Kingdom and EU	Sunday 29 March	Sunday 25 October	01:00 UTC
Australia (NSW, VIC, SA, TAS, ACT)	Ended Sunday 5 April, resumes Sunday 4 October	-	02:00 - 03:00 local
New Zealand	Sunday 5 April (ended)	Sunday 27 September (starts)	02:00 - 03:00 local
Chile (mainland)	Ended Saturday 4 April, resumes Saturday 5 September	-	24:00 local

The gap between the US and EU spring transitions lasts three weeks. From 8 March to 28 March 2026, New York is only four hours behind London instead of the usual five. A recurring 09:00 London to 04:00 New York meeting actually fires at 05:00 New York during this window, which is the single most common source of calendar drift on diverse teams.

Global Business Hours at a Glance

Trading floors and headquarter offices cluster into six rough bands around the clock. The overlap windows are when cross-border calls fit into normal working hours.

Market	Local Trading Hours	UTC Hours (DST)	Overlap With
Tokyo Stock Exchange	09:00 - 15:30 JST	00:00 - 06:30 UTC	Sydney morning, Frankfurt pre-open
Shanghai Stock Exchange	09:30 - 15:00 CST	01:30 - 07:00 UTC	Tokyo, London pre-open
London Stock Exchange	08:00 - 16:30 BST	07:00 - 15:30 UTC	Frankfurt all day, NY 13:30 onward
New York Stock Exchange	09:30 - 16:00 EDT	13:30 - 20:00 UTC	London 13:30 - 15:30, Toronto all day
Australian Securities Exchange	10:00 - 16:00 AEDT	23:00 - 05:00 UTC (prev day)	Singapore afternoon, Tokyo morning

The London-New York overlap of 13:30 to 15:30 UTC is the deepest liquidity window of the day in global finance, which is why most cross-Atlantic business meetings and economic data releases are scheduled in that two-hour slice.

Timezone Quirks Worth Knowing

Not every part of the world uses a clean hour offset from UTC. Several countries use fractional offsets or make political choices that override geography.

• Nepal (UTC+5:45) - the only country on a 45-minute offset, chosen to honour the meridian through Gaurishankar peak.
• Chatham Islands (UTC+12:45) - New Zealand's remote archipelago uses a 45-minute offset separate from mainland NZ.
• China (UTC+8 everywhere) - a single zone spans 5 geographic hours of longitude, so sunrise in western Xinjiang can be as late as 10:00 local time.
• Russia (UTC+2 to UTC+12) - eleven separate zones, none of which observe DST as of the 2011 abolition.
• Arizona and Hawaii - opted out of US DST under the Uniform Time Act. Navajo Nation inside Arizona does observe DST, so border signs flip at county lines.
• Kiribati (UTC+14) - the furthest-forward time zone in the world, used by the Line Islands. Kiribati shifted the date line east in 1995 to keep its territory on the same calendar day.
• Samoa (UTC+13) - skipped 30 December 2011 entirely, jumping from UTC-11 to UTC+13 to align with New Zealand and Australia trading hours.

Common Mistakes When Scheduling Across Timezones

Most scheduling failures come from a handful of predictable errors. The list below covers what actually breaks calendars, based on real developer and operations support queues.

• Ignoring the DST gap weeks. Assuming the New York-London offset is always five hours guarantees mis-scheduled meetings in March and late October.
• Using "EST" year-round. The US East Coast is only on EST (UTC-5) in winter - the correct year-round identifier is America/New_York, which resolves to EDT in summer.
• Treating India or China as a multi-zone country. Both use one offset nationwide, so Asia/Kolkata covers the entire subcontinent and Asia/Shanghai covers all of China.
• Outlook recurring meeting drift. Older Exchange servers stored recurrences in local time without a zone identifier, so when the originating user's DST changes but the invitee's does not, the meeting slowly drifts by an hour until someone notices.
• Forgetting the International Date Line. A Monday afternoon call from Sydney lands on a Monday morning in Los Angeles, but a Monday morning call from Sydney lands on a Sunday evening in LA. The date stamp flips before the clock does.
• Storing wall-clock times without a zone. Logging "14:30" with no timezone attached is the single most common root cause of data-reconciliation bugs when teams span continents.

Sources

• IANA - Time Zone Database
• timeanddate.com - Daylight Saving Time 2026 Dates
• GOV.UK - When Do the Clocks Change
• NIST - Daylight Saving Time
• NYSE - Hours and Calendars
• London Stock Exchange - Trading Hours
• MDN - Intl.DateTimeFormat