Global Time Zone Converter & Meeting Planner
Convert times between world time zones (UTC, EST, PST, GMT, JST, ICT) and plan international meetings.
Hanoi
New York
Interactive Time Zone & Schedule Planner
Instant 0ms conversion, auto DST adjustment & world clock comparison
Multi-City 24-Hour Interactive Timeline Matrix
Click any hour cell to synchronize all global city clocks simultaneously
Calculation Metrics
Quick Answer & Understanding Your Result
A Time Zone converter translates local time between global regions by calculating the differential between their respective Coordinated Universal Time (UTC) offsets, accounting for Daylight Saving Time (DST) rules.
Major Global Financial & Tech Time Zones
- UTC / GMT (0:00): Coordinated Universal Time baseline (London Winter / Accra).
- EST / EDT (UTC-5 / UTC-4): US Eastern Time (New York, Toronto, Washington DC).
- PST / PDT (UTC-8 / UTC-7): US Pacific Time (San Francisco, Los Angeles, Seattle).
- CET / CEST (UTC+1 / UTC+2): Central European Time (Paris, Berlin, Rome, Madrid).
- ICT (UTC+7): Indochina Time (Vietnam, Thailand, Indonesia/Jakarta).
- JST / KST (UTC+9): Japan & Korea Standard Time (Tokyo, Seoul).
Select your origin time zone and target destination cities above to synchronize clocks and find overlapping international business hours.
Formula & Calculation Logic
Mathematical FormulaBased on the IANA Time Zone Database (tzdb) maintaining historical and future DST transition rules.
Step-by-Step Guide
Select Base Location & Time
Choose your home city/time zone and set the reference time.
Add Target Cities
Add international cities (e.g., New York, London, Tokyo, Sydney).
Slide Interactive Timeline
Drag the 24-hour slider to visualize simultaneous times across all locations.
Find Green Overlap Hours
Identify mutually convenient working hours (9:00 AM – 5:00 PM) across all participants.
Worked Examples Table
| Example | Input Values | Calculated Result | Explanation |
|---|---|---|---|
| 9:00 AM in New York (EDT - UTC-4) to Vietnam (ICT - UTC+7) | 7 - (-4) = 11 hours ahead. | ||
| 3:00 PM in London (GMT - UTC+0) to Tokyo (JST - UTC+9) | 15:00 + 9 hours = 24:00 (Next day). |
Frequently Asked Questions
Evidence-Based Methodology & Authoritative References
IANA Time Zone Database (tzdb)
BIPM - Bureau International des Poids et Mesures (UTC Time Standard)
Standard: ISO / W3C / IETF Authoritative Domain Standard
Formula: Target Time = Origin Time - Origin_UTC_Offset + Target_UTC_Offset
Last Reviewed: August 21, 2026
Primary Source: IANA Time Zone Database (tzdb)
Reference Document: BIPM - Bureau International des Poids et Mesures (UTC Time Standard)
Computation Privacy: 100% client-side 0ms computation, zero data retention
Calculated results are modeled based on standard scientific and mathematical formulas. Please verify with domain-specific technical documentation for specialized applications.
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Calculated results are modeled based on standard scientific and mathematical formulas. Please verify with domain-specific technical documentation for specialized applications.