What Is an IANA Time Zone?
An IANA time zone is a database name such as America/New_York or Europe/London that describes local time rules for a real region.
At a glance
| Format | Usually Area/Location, such as Europe/Paris. |
|---|---|
| Why it matters | IANA names include daylight-saving and historic offset rules. |
| Browse | Open the full IANA time zones list. |
IANA names are more exact than abbreviations
Short time-zone labels can be ambiguous. IANA names point to a specific rule set.
A name like EST can mean different things
EST is a useful search label, but abbreviations can overlap across regions. An IANA time zone such as America/New_York carries the rule history needed to calculate current local time.
- Use abbreviation pages for quick discovery.
- Use IANA pages for technical accuracy.
- Use city pages when a human location is more helpful.
IANA names handle DST rules
Many locations change offset during daylight saving time. IANA data keeps those rules tied to the place so clocks and conversions stay accurate.
How to read an IANA time-zone name
Most IANA names use an area and location separated by a slash.
Area tells you the broad region
Examples include America, Europe, Asia, Africa, Australia, and Pacific. The second part is usually a city or representative location.
- America/Chicago represents Central Time rules for that region.
- Asia/Tokyo represents Japan Standard Time rules.
- Europe/London represents London with GMT/BST changes.
Use IANA names in technical tools
When you build a calendar, clock widget, or converter, IANA names are safer than raw offsets. Raw offsets do not know when daylight saving time changes.
Related tools and guides
Frequently asked questions
What is an example of an IANA time zone?
America/New_York, Europe/London, Asia/Tokyo, and Australia/Sydney are common IANA time-zone names.
Why not just use UTC offset?
A UTC offset tells you the difference right now, but it does not include daylight-saving rules or historic changes.
Are IANA time zones useful for websites?
Yes. They are the standard way to choose accurate local time in web browsers, calendars, and scheduling tools.