Time Zone Abbreviation Lookup
Look up time zone abbreviations like PST, AEDT, IST and their UTC offsets.
Overview
The Time Zone Abbreviation Lookup is a searchable table of timezone abbreviations — PST, EST, GMT, UTC, IST, AEDT, JST — together with their full names, UTC offsets and a representative city. It also shows whether the abbreviation is a daylight-saving variant (EDT vs EST, BST vs GMT) and the IANA timezone identifier you would pass to a date library.
The tool is for meeting organisers reading an email like "let's chat at 3pm AEDT", developers normalising user timezone input and travellers double-checking a flight itinerary. Long-tail queries it covers include "what does CET mean", "PST vs PDT offset", "IST India vs Ireland" and "AEDT Sydney offset from UTC".
How it works
The dataset pairs each common abbreviation with its UTC offset, its full descriptive name and the matching IANA zone identifier (e.g. PST maps to America/Los_Angeles in winter). Where the same abbreviation is used in multiple regions — "IST" stands for both Indian Standard Time and Irish Standard Time — the lookup returns both with a disambiguation note.
The search is a case-insensitive prefix-and-contains match across the abbreviation, the full name and the example city. The IANA zone identifier is the canonical form for software because it handles daylight saving transitions automatically; abbreviations are for humans.
Examples
PST → Pacific Standard Time → UTC−8 → America/Los_Angeles (winter)
GMT → Greenwich Mean Time → UTC+0 → Europe/London (winter)
IST → India Standard Time → UTC+5:30 → Asia/Kolkata
AEDT → Australian Eastern Daylight Time → UTC+11 → Australia/Sydney (summer)
FAQ
Why is "IST" ambiguous?
It stands for India Standard Time (UTC+5:30), Irish Standard Time (UTC+1) and Israel Standard Time (UTC+2). The lookup returns all three. Always use the IANA identifier (Asia/Kolkata, Europe/Dublin, Asia/Jerusalem) in software.
What's the difference between EST and EDT?
EST (Eastern Standard Time) is UTC−5 and applies in winter. EDT (Eastern Daylight Time) is UTC−4 and applies in summer. The IANA zone America/New_York switches between them automatically.
Why do some abbreviations have no daylight variant?
Some zones do not observe daylight saving at all. India (IST), Japan (JST) and China (CST) stay at one offset year-round, so there's only one abbreviation.
Is UTC the same as GMT?
For everyday purposes, yes — they are within a second of each other. UTC is the formally defined modern standard; GMT is the older astronomical term. The UK still uses GMT in winter.
Why use IANA names instead of abbreviations?
Abbreviations are ambiguous and don't track DST changes. IANA names like Europe/London encode the full history of offset changes for that location, so a date library can convert correctly between any two timestamps regardless of historical DST rules.