About Time Zones
Time zones divide the world into regions that observe the same standard time. This tool uses the browser's Intl.DateTimeFormat API for accurate Day Light Saving Time (DST) conversions regardless of your location. All processing happens entirely in your local browser — no request is ever made to any server.
Frequently Asked Questions
What is UTC and why is it used as a reference?
UTC (Coordinated Universal Time) is the primary time standard by which the world regulates clocks and time. It has no daylight saving time adjustments, making it a stable reference point. All time zones are expressed as offsets from UTC: New York is UTC-5 (or UTC-4 in summer), London is UTC+0 (UTC+1 in summer), Tokyo is UTC+9.
How does Daylight Saving Time affect conversions?
DST shifts the clock forward 1 hour in spring and back in autumn. Not all countries observe DST, and those that do change on different dates. This tool uses the browser's Intl.DateTimeFormat API, which knows the DST rules for each timezone and applies them automatically for the selected date and time.
How do I schedule a meeting between New York and London?
New York is typically 5 hours behind UTC (EST) or 4 hours in summer (EDT). London is UTC+0 (GMT) or UTC+1 in summer (BST). The difference is usually 5 hours (New York 9 AM = London 2 PM), or 4 hours when BST is active.
What is the difference between GMT and UTC?
For most practical purposes, GMT and UTC are the same. The technical difference is that GMT is a time zone (used in the UK in winter) while UTC is a time standard that doesn't observe DST. When scheduling across systems, UTC is more reliable because it never changes — GMT can be confused with BST (British Summer Time) in casual usage.
Does this tool account for half-hour and 45-minute offset time zones?
Yes. Some time zones have non-standard offsets: India (UTC+5:30), Iran (UTC+3:30), Nepal (UTC+5:45), and parts of Australia (UTC+9:30). The converter uses IANA timezone data which handles all offsets correctly.