WorldTime Grid tool
UTC Offset vs IANA Time Zone
Compare a fixed UTC offset with a named zone whose rules can vary by date.
America/New_York is a named IANA time zone. Its UTC offset is calculated separately for each date.
2026-01-15: UTC-05:00
2026-07-15: UTC-04:00
A fixed value such as UTC−5 cannot describe seasonal changes or later rule updates. Save the IANA zone name when the location matters.
Method and limitations
This tool uses named IANA time zones and calculates the applicable offset for the selected date. Time-zone rules can change, browser data versions can differ, and important future events should be confirmed in participants’ calendars.
No account or server database is required. Values entered into the calculator remain in the browser unless you deliberately create and share a URL.