Timezone Converter
Convert times between world time zones
How to use Timezone Converter
Convert times between different world time zones. Supports all major cities and UTC offsets. Free online timezone converter tool.
When do you need to convert time zones?
As remote work and global collaboration have become standard, time zone awareness is a daily professional skill. Scheduling across time zones incorrectly leads to missed meetings, late deliveries, and damaged relationships.
- Scheduling meetings: A team spanning New York, London, and Singapore needs to find overlap hours. 9am New York = 2pm London = 9pm Singapore — only the first two are reasonable working hours.
- International deadlines: "Submission closes midnight" — midnight which timezone? A developer in Tokyo needs to know what that means locally before committing to a deadline.
- Live events and webinars: Converting a webinar time for attendees in multiple countries — and communicating the result clearly to avoid confusion.
- Financial markets: Stock exchanges operate in specific local times. NYSE opens at 9:30am EST; LSE at 8am GMT; TSE at 9am JST. Traders worldwide track these in their local time.
- Travel planning: Calculate the local time at your destination for booking hotels, planning connections, and coordinating pickups.
Daylight Saving Time (DST): Many countries change their clocks seasonally — adding complexity to time zone conversion. The US and EU have different DST start/end dates; some countries (Japan, China, India) do not observe DST at all. Always verify DST when scheduling across regions during transition periods.
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. It is essentially the modern successor to Greenwich Mean Time (GMT), maintained by atomic clocks and adjusted with leap seconds. All time zones are expressed as UTC offsets: EST = UTC-5, CET = UTC+1, IST = UTC+5:30. Using UTC as a reference eliminates ambiguity in international communication.
What is the difference between GMT and UTC?
GMT (Greenwich Mean Time) is a timezone — the local time at the Royal Observatory in Greenwich, London. UTC is a time standard — a mathematical construct maintained by atomic clocks. They are numerically identical (no offset between them) but conceptually different. UTC is the preferred term in technical contexts; GMT is still used colloquially for the UTC+0 timezone.
Why does India have a half-hour offset (UTC+5:30)?
India chose UTC+5:30 to best serve its entire geographic span while using a single timezone. A 30-minute offset reflects a compromise between the needs of eastern and western India. Similar half-hour offsets exist for: Australia/Lord Howe Island, Iran (UTC+3:30), Afghanistan (UTC+4:30), and Myanmar (UTC+6:30). Nepal uses UTC+5:45 — a 15-minute offset.
What is the International Date Line?
The International Date Line (IDL) is an imaginary line at approximately 180° longitude where the calendar date changes. Crossing it westward moves you one day forward; eastward, one day back. It zigzags around island nations to avoid splitting countries across dates. Traveling west from UTC-12 to UTC+14 (both near the IDL) means a 26-hour difference.
How do I handle daylight saving time in programming?
Store all timestamps in UTC in your database. Convert to local time only for display, using the user's timezone identifier (e.g., 'America/New_York', not 'EST'). Never store 'EST' — it is ambiguous during DST transitions. Use a timezone library (moment-timezone, Luxon in JavaScript; pytz or zoneinfo in Python) that handles DST rules correctly.
Time zone converter vs world clock vs calendar with time zones
A time zone converter answers "what time is it there when it is X here?" — useful for scheduling specific moments. A world clock shows current time in multiple cities simultaneously — useful for awareness of where colleagues are in their day. A calendar with time zone support (Google Calendar, Outlook) displays events in multiple zones and handles DST automatically — the best tool for managing ongoing international scheduling. For quick one-off conversions, this tool is fastest.