The vocabulary of the World Time API

The 4 fields and concepts you'll meet in the response — defined in plain English, each with a real example value.

4 terms
Timezones3

IANA Timezone

A timezone identifier from the IANA Time Zone Database (e.g., America/New_York).

The standard format for representing timezones, maintained by IANA. Includes historical data about timezone changes and DST rules. Preferred over abbreviations like EST/PST which can be ambiguous.

ExampleAmerica/Los_Angeles, Europe/Paris, Asia/Tokyo

UTC Offset

The difference in hours and minutes from Coordinated Universal Time (UTC).

Expressed as +/- hours from UTC. For example, EST is UTC-5 and JST is UTC+9. Offsets change when DST is in effect.

ExampleUTC-05:00, UTC+09:00

Daylight Saving Time

The practice of advancing clocks during warmer months to extend evening daylight.

Not all timezones observe DST, and the dates of transition vary by country. Our API handles DST automatically and indicates when it's in effect.

ExampleUS: March to November, EU: March to October

Time Formats1

Unix Timestamp

The number of seconds since January 1, 1970 (UTC), also called Epoch time.

A timezone-independent way to represent a moment in time. Useful for storing and comparing times across systems. Convert to local time for display.

Example1705325445 = 2024-01-15T14:30:45Z

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