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World Time Zone Converter

Convert times between world cities. Auto-handles DST, shows working hours, supports 22 popular timezones. Uses IANA standard.

All tools

Source time

Source timezone

Date & time

Target timezones

Time Zone Converter uses Intl.DateTimeFormat with IANA timezones — automatically handles DST (daylight saving). Red bands on the timeline = outside 9-17h working hours.

When you need a timezone converter

International team meetings: working with US/EU teammates — know what "9 AM Vietnam" is in SF, NYC, London.
Schedule meetings: send Calendly invites across timezones — pick a slot that works for everyone.
Trading stocks: know when each market opens, plus pre-market and after-hours sessions.
Streaming: Twitch, YouTube live — when is your US audience awake? Your EU audience?
Remote work: async standups with teammates in Sydney, Bangalore, NYC — find overlap windows.

What is DST (Daylight Saving Time)?

Each spring, several countries (US, EU, Australia) shift clocks forward 1 hour. In autumn they shift back. The goal: make better use of daylight and reduce electricity for lighting.

Vietnam, Thailand, Indonesia, Singapore, China, Japan, Korea: NO DST.
US: changes twice a year. NYC is EDT (UTC-4) Mar-Nov, EST (UTC-5) Nov-Mar.
EU: changes on the last Sunday of March and October. London is BST (UTC+1) in summer, GMT (UTC+0) in winter.
Australia: opposite seasons — Sydney is AEDT (UTC+11) Oct-Apr, AEST (UTC+10) Apr-Oct.

The tool uses standard Intl.DateTimeFormat — DST is handled correctly for any date.