Time Zone Tool
Convert times across global time zones for international project coordination.
Calculator
No signup required. Results are indicative—verify for your standards.
10:00 — IST (India, UTC+5:30)
08:30 — GST (Dubai, UTC+4)
05:30 — CET (Germany winter, UTC+1)
06:30 — CEST (Germany summer, UTC+2)
04:30 — GMT/UTC
23:30 (prev day) — EST (New York winter, UTC-5)
00:30 — EDT (New York summer, UTC-4)
12:30 — CST (China, UTC+8)
12:30 — SGT (Singapore, UTC+8)
13:30 — JST (Japan, UTC+9)
14:30 — AEST (Sydney winter, UTC+10)
Formula
UTC offset conversion: Target time = Source time − Source UTC offset + Target UTC offset. IST = UTC + 5:30. GST (Dubai) = UTC + 4. CET = UTC + 1 (UTC + 2 in summer CEST).
Example calculation
Meeting at 10:00 IST: UTC = 10:00 − 5:30 = 04:30 UTC. EST (New York, winter) = UTC − 5 = 23:30 previous day. GST (Dubai) = UTC + 4 = 08:30. CET (Germany, winter) = UTC + 1 = 05:30.
Engineering notes
Note that Daylight Saving Time (DST) is observed in Europe, North America, and Australia but NOT in India, Middle East, China, or Japan. DST shifts clocks 1 hour forward in summer — US EST becomes EDT (UTC−4), CET becomes CEST (UTC+2). Always clarify whether a stated time is DST or standard time.
When to use this calculator
- Supplier calls — schedule video conferences with US, European, or Chinese equipment manufacturers
- Project reporting — align daily status report submission times across internationally distributed project teams
- Factory acceptance testing (FAT) — coordinate live FAT attendance for overseas buyers
- Shipping deadlines — convert port cutoff times to local IST for shipping document submission
- Contract milestones — clarify whether "end of business day" means local time or a specified reference time zone
Frequently asked questions
- What is IST and how does it differ from UTC?
- IST (Indian Standard Time) = UTC + 5 hours 30 minutes. India uses a single time zone for the entire country, unlike some large countries (USA, Australia, Russia) that span multiple time zones. IST does not observe daylight saving time, so the offset from countries that do (USA, Europe) changes by 1 hour in their summer. IST is also written as GMT+5:30.
- Why do international meeting times shift during summer?
- Many countries observe Daylight Saving Time (DST): clocks are moved forward 1 hour in spring and back in autumn. The USA shifts from EST (UTC−5) to EDT (UTC−4) in March. Europe shifts from CET (UTC+1) to CEST (UTC+2) in late March. India does not observe DST, so a 10:00 IST meeting that is normally 09:30 GST and 04:30 UTC becomes 1 hour different from European perspectives when their DST is in effect.
- What time zones should I know for common international industrial trading partners?
- China/Hong Kong/Singapore: CST/SGT = UTC+8. Japan: JST = UTC+9. South Korea: KST = UTC+9. UAE/Dubai: GST = UTC+4. Germany/EU: CET = UTC+1, CEST = UTC+2 (summer). UK: GMT = UTC+0, BST = UTC+1 (summer). USA East: EST = UTC−5, EDT = UTC−4 (summer). USA West: PST = UTC−8, PDT = UTC−7 (summer). Australia East: AEST = UTC+10, AEDT = UTC+11 (summer).