Time zone guide

Time Zone Abbreviations

Short codes like EST, PST, CET, and IST are convenient, but they are not always unique. This guide explains the abbreviations people most often use, where daylight saving changes the code, and when to use a full IANA time zone instead.

Best for humans

Abbreviations work well in text when the region is obvious, such as 9:00 AM EST for a US audience.

Risky for automation

Many codes are reused. A calendar invite should use a city or IANA identifier, not just CST or IST.

Date matters

Daylight-saving regions often switch between standard and daylight abbreviations during the year.

Common time zone abbreviations

Offsets below are typical standard or daylight offsets. Always check the date for daylight-saving regions.

Abbreviation Common meaning Typical offset Safer IANA example
UTCCoordinated Universal TimeUTC+0Etc/UTC
GMTGreenwich Mean TimeUTC+0Europe/London
EST / EDTEastern Standard / Daylight TimeUTC-5 / UTC-4America/New_York
CST / CDTCentral Standard / Daylight TimeUTC-6 / UTC-5America/Chicago
MST / MDTMountain Standard / Daylight TimeUTC-7 / UTC-6America/Denver
PST / PDTPacific Standard / Daylight TimeUTC-8 / UTC-7America/Los_Angeles
CET / CESTCentral European Standard / Summer TimeUTC+1 / UTC+2Europe/Paris
BSTBritish Summer TimeUTC+1Europe/London
JSTJapan Standard TimeUTC+9Asia/Tokyo
KSTKorea Standard TimeUTC+9Asia/Seoul
AEST / AEDTAustralian Eastern Standard / Daylight TimeUTC+10 / UTC+11Australia/Sydney
NZST / NZDTNew Zealand Standard / Daylight TimeUTC+12 / UTC+13Pacific/Auckland

Ambiguous abbreviations to watch

CST can mean Central Standard Time in North America, China Standard Time, or Cuba Standard Time. Use the China time zones guide when CST means China Standard Time.

IST can mean India Standard Time, Irish Standard Time, or Israel Standard Time depending on the audience and date. Use the India time zones guide when IST means India Standard Time.

BST usually means British Summer Time in UK scheduling, but the same letters can appear in other regional contexts. Use the UK time zones guide when the date may fall in either GMT or BST.

Use IANA names for exact scheduling

For software, calendars, travel planning, and recurring meetings, use IANA time zones such as America/New_York, Europe/London, or Asia/Tokyo. These identifiers encode the local daylight-saving rules for a place.

Open converter Compare two places

Quick FAQ

Is UTC the same as GMT?

For everyday scheduling they often point to the same clock time, UTC+0. UTC is the modern standard used by computers and timekeeping systems; GMT is a historical term still common in UK and travel contexts.

Why do EST and EDT both exist?

EST is Eastern Standard Time, used outside daylight saving. EDT is Eastern Daylight Time, used during daylight saving. The offset changes by one hour.

What should I put in an international meeting invite?

Use a city-based time zone or IANA name, then include a friendly abbreviation for readers. For example: 10:00 AM America/New_York (EDT). You can also start from the time zone clocks hub for common zones.

EST to PST

Convert Eastern Time to Pacific Time with date-aware daylight-saving context.

 PST to EST

Convert Pacific Time to Eastern Time with date-aware daylight-saving context.

 EST to CST

Convert Eastern Time to Central Time with date-aware daylight-saving context.

 CST to EST

Convert Central Time to Eastern Time with date-aware daylight-saving context.

 PST to CST

Convert Pacific Time to Central Time with date-aware daylight-saving context.

 CST to PST

Convert Central Time to Pacific Time with date-aware daylight-saving context.

 UTC to EST

Convert Coordinated Universal Time to Eastern Time with date-aware daylight-saving context.

 GMT to EST

Convert Greenwich Mean Time to Eastern Time with date-aware daylight-saving context.

 EST to IST

Convert Eastern Time to India Standard Time with date-aware daylight-saving context.

 IST to EST

Convert India Standard Time to Eastern Time with date-aware daylight-saving context.

 PST to IST

Convert Pacific Time to India Standard Time with date-aware daylight-saving context.

 IST to PST

Convert India Standard Time to Pacific Time with date-aware daylight-saving context.

 UTC to PST

Convert Coordinated Universal Time to Pacific Time with date-aware daylight-saving context.

 PST to UTC

Convert Pacific Time to Coordinated Universal Time with date-aware daylight-saving context.

 UTC to CST

Convert Coordinated Universal Time to Central Time with date-aware daylight-saving context.

 CST to UTC

Convert Central Time to Coordinated Universal Time with date-aware daylight-saving context.

 EST to GMT

Convert Eastern Time to Greenwich Mean Time with date-aware daylight-saving context.

 GMT to PST

Convert Greenwich Mean Time to Pacific Time with date-aware daylight-saving context.

 CET to EST

Convert Central European Time to Eastern Time with date-aware daylight-saving context.

 EST to CET

Convert Eastern Time to Central European Time with date-aware daylight-saving context.

 UTC to IST

Convert UTC to India Standard Time with date-aware daylight-saving context.

 IST to UTC

Convert India Standard Time to UTC with date-aware daylight-saving context.

 GMT to IST

Convert Greenwich Mean Time to India Standard Time with date-aware daylight-saving context.

 IST to GMT

Convert India Standard Time to Greenwich Mean Time with date-aware daylight-saving context.

 CET to PST

Convert Central European Time to Pacific Time with date-aware daylight-saving context.

 PST to CET

Convert Pacific Time to Central European Time with date-aware daylight-saving context.

 UTC to CET

Convert UTC to Central European Time with date-aware daylight-saving context.

 CET to UTC

Convert Central European Time to UTC with date-aware daylight-saving context.

 GMT to CET

Convert Greenwich Mean Time to Central European Time with date-aware daylight-saving context.

 CET to GMT

Convert Central European Time to Greenwich Mean Time with date-aware daylight-saving context.

 PST to GMT

Convert Pacific Time to Greenwich Mean Time with date-aware daylight-saving context.

 CST to GMT

Convert Central Time to Greenwich Mean Time with date-aware daylight-saving context.

 PST to JST

Convert Pacific Time to Japan Standard Time with date-aware daylight-saving context.

 EST to JST

Convert Eastern Time to Japan Standard Time with date-aware daylight-saving context.

 GMT to JST

Convert Greenwich Mean Time to Japan Standard Time with date-aware daylight-saving context.

 EST to SGT

Convert Eastern Time to Singapore Time with date-aware daylight-saving context.

 SGT to EST

Convert Singapore Time to Eastern Time with date-aware daylight-saving context.

 PST to SGT

Convert Pacific Time to Singapore Time with date-aware daylight-saving context.

 SGT to PST

Convert Singapore Time to Pacific Time with date-aware daylight-saving context.

 GMT to SGT

Convert Greenwich Mean Time to Singapore Time with date-aware daylight-saving context.

 SGT to GMT

Convert Singapore Time to Greenwich Mean Time with date-aware daylight-saving context.

 EST to AEST

Convert Eastern Time to Australian Eastern Time with date-aware daylight-saving context.

 AEST to EST

Convert Australian Eastern Time to Eastern Time with date-aware daylight-saving context.

 PST to AEST

Convert Pacific Time to Australian Eastern Time with date-aware daylight-saving context.

 AEST to PST

Convert Australian Eastern Time to Pacific Time with date-aware daylight-saving context.

 EST to MST

Convert Eastern Time to Mountain Time with date-aware daylight-saving context.

 MST to EST

Convert Mountain Time to Eastern Time with date-aware daylight-saving context.

 PST to MST

Convert Pacific Time to Mountain Time with date-aware daylight-saving context.

 MST to PST

Convert Mountain Time to Pacific Time with date-aware daylight-saving context.

 CST to MST

Convert Central Time to Mountain Time with date-aware daylight-saving context.

 MST to CST

Convert Mountain Time to Central Time with date-aware daylight-saving context.

 UTC to MST

Convert UTC to Mountain Time with date-aware daylight-saving context.

 MST to UTC

Convert Mountain Time to UTC with date-aware daylight-saving context.

 GMT to MST

Convert Greenwich Mean Time to Mountain Time with date-aware daylight-saving context.

 MST to GMT

Convert Mountain Time to Greenwich Mean Time with date-aware daylight-saving context.

 UTC to GMT

Convert UTC to Greenwich Mean Time with date-aware daylight-saving context.

 GMT to UTC

Convert Greenwich Mean Time to UTC with date-aware daylight-saving context.

 UTC to JST

Convert UTC to Japan Standard Time with date-aware daylight-saving context.

 JST to UTC

Convert Japan Standard Time to UTC with date-aware daylight-saving context.

 JST to EST

Convert Japan Standard Time to Eastern Time with date-aware daylight-saving context.

 US Time Zones

Review Eastern, Central, Mountain, Pacific, Alaska, and Hawaii daylight-saving context.

Data, review, and privacy

Abbreviations such as CST, IST, and GMT can be ambiguous, so this guide treats them as reading aids rather than authoritative time sources. Use these links to review the data method, editorial standards, correction path, and privacy disclosures behind the guide.

Data accuracy

How offsets, IANA zones, and correction reports are handled.

 Editorial policy

How explanatory guides are reviewed and separated from ads.

 Feedback

Report a confusing label, missing route, or outdated example.

 Privacy policy

Review cookies, analytics, advertising, and local storage.