IANA Time Zone Database — List, UTC Offsets & Live Converter
America/New_York or Asia/Tokyo to their UTC offsets and daylight-saving rules. A few anchors: New York = UTC-5 (EST) / UTC-4 (EDT), London = UTC+0 (GMT) / UTC+1 (BST), Tokyo = UTC+9 (JST, no DST), Sydney = UTC+10 (AEST) / UTC+11 (AEDT). Use the converter below for the exact current time in any two zones — it reads your browser's embedded tz database, so it is always current through DST changes. Source: IANA tz database; retrieved 2026-08-14.Quick Reference
Live time-zone converter
Zone B is — of Zone A right now. Times resolve live from your browser's embedded IANA timezone database, so daylight-saving transitions are always current.
Major IANA time zones and their UTC offsets
| Zone label | IANA name | Standard | Daylight | Sample cities |
|---|---|---|---|---|
| Eastern Time (ET) | America/New_York | UTC-5 | UTC-4 | New York, Miami, Atlanta |
| Central Time (CT) | America/Chicago | UTC-6 | UTC-5 | Chicago, Dallas, Houston |
| Mountain Time (MT) | America/Denver | UTC-7 | UTC-6 | Denver, Phoenix (no DST) |
| Pacific Time (PT) | America/Los_Angeles | UTC-8 | UTC-7 | Los Angeles, Seattle, San Francisco |
| Arizona (MST, no DST) | America/Phoenix | UTC-7 | no DST | Phoenix, Tucson |
| Alaska Time (AKT) | America/Anchorage | UTC-9 | UTC-8 | Anchorage |
| Hawaii (HST, no DST) | Pacific/Honolulu | UTC-10 | no DST | Honolulu |
| Eastern Time (ET) | America/Toronto | UTC-5 | UTC-4 | Toronto, Ottawa, Montreal |
| Pacific Time (PT) | America/Vancouver | UTC-8 | UTC-7 | Vancouver |
| Central Time (CT) | America/Mexico_City | UTC-6 | UTC-5 | Mexico City |
| Brasília Time (BRT) | America/Sao_Paulo | UTC-3 | no DST | São Paulo, Rio de Janeiro |
| Argentina Time (ART) | America/Argentina/Buenos_Aires | UTC-3 | no DST | Buenos Aires |
| Greenwich Mean Time (GMT) | Europe/London | UTC+0 | UTC+1 | London |
| Central European Time (CET) | Europe/Paris | UTC+1 | UTC+2 | Paris |
| Central European Time (CET) | Europe/Berlin | UTC+1 | UTC+2 | Berlin |
| Central European Time (CET) | Europe/Madrid | UTC+1 | UTC+2 | Madrid |
| Central European Time (CET) | Europe/Rome | UTC+1 | UTC+2 | Rome |
| Moscow Time (MSK) | Europe/Moscow | UTC+3 | no DST | Moscow |
| Eastern European Time (EET) | Africa/Cairo | UTC+2 | no DST | Cairo |
| South Africa Standard Time | Africa/Johannesburg | UTC+2 | no DST | Johannesburg |
| West Africa Time (WAT) | Africa/Lagos | UTC+1 | no DST | Lagos |
| Gulf Standard Time (GST) | Asia/Dubai | UTC+4 | no DST | Dubai |
| India Standard Time (IST) | Asia/Kolkata | UTC+5:30 | no DST | Mumbai, Delhi |
| Indochina Time (ICT) | Asia/Bangkok | UTC+7 | no DST | Bangkok |
| China Standard Time (CST) | Asia/Shanghai | UTC+8 | no DST | Beijing, Shanghai |
| Hong Kong Time (HKT) | Asia/Hong_Kong | UTC+8 | no DST | Hong Kong |
| Singapore Standard Time (SGT) | Asia/Singapore | UTC+8 | no DST | Singapore |
| Japan Standard Time (JST) | Asia/Tokyo | UTC+9 | no DST | Tokyo |
| Korea Standard Time (KST) | Asia/Seoul | UTC+9 | no DST | Seoul |
| Australian Eastern Time (AET) | Australia/Sydney | UTC+10 | UTC+11 | Sydney, Melbourne |
| Australian Western Time (AWT) | Australia/Perth | UTC+8 | no DST | Perth |
| New Zealand Time (NZST) | Pacific/Auckland | UTC+12 | UTC+13 | Auckland |
Why the IANA database matters
- One name, correct history. A single IANA id encodes every past and future offset change, including obsolete rules — essential for scheduling across years.
- Daylight saving, handled. The converter above applies the right offset for today, so you never mis-compute a meeting because a zone “sprang forward” or “fell back.”
- Cross-platform. The same zone names work in browsers, servers, phones and calendars, which is why “America/New_York” is more reliable than “EST.”
Frequently Asked Questions
What is the IANA time zone database?
The IANA tz database (also called tzdata or zoneinfo) is the reference table that maps region names such as "America/New_York" to their historical and planned UTC offsets, including daylight-saving rules. Operating systems, browsers and programming languages embed it so clocks stay correct across the year and across history.
How do I find my IANA time zone?
It is the "Area/Location" string your device stores, e.g. "Europe/London" or "Asia/Tokyo". On most systems it appears in the date/time settings as a named city. The table on this page lists the common ones; pick the row whose sample cities match your location.
Why do time zone offsets change during the year?
Many zones observe daylight saving time: they shift forward by one hour in spring and back in autumn. So "America/New_York" is UTC-5 in winter (EST) and UTC-4 in summer (EDT). Southern-hemisphere zones such as Australia/Sydney shift on the opposite schedule. The live converter above always shows the current offset.
What is the difference between EST and EDT?
They are the same physical zone at different times of year. EST (Eastern Standard Time) is the winter offset UTC-5; EDT (Eastern Daylight Time) is the summer offset UTC-4. IANA uses one name, "America/New_York", and applies the correct offset automatically.
How do I convert a time between two zones?
Use the live converter above: pick Zone A and Zone B and it shows both current local times plus the difference (e.g. Tokyo is 13 hours ahead of New York in January, 14 in July). For a fixed historical or future moment, convert by adding the offset difference and watch for DST boundaries.