Time Zone Calculator
Convert time between any of the world's time zones. Plan international meetings and travel across time zones. Convert between time zones and calculate the time difference. Plan meetings across multiple time zones with accurate conversions.
Enter Values
Fill in the fields and press Calculate to see instant results.
Time Zone Calculator – Convert Times Between World Time Zones
The Time Zone Calculator instantly converts any time from one world time zone to another. Whether you are scheduling an international meeting, calling a friend abroad, planning a flight arrival, or coordinating a global team standup, this tool eliminates the mental math of UTC offsets and Daylight Saving Time adjustments.
Time zone conversion seems simple but is riddled with traps: Daylight Saving Time shifts offsets by 1 hour in some countries but not others, India and several other nations use non-standard half-hour offsets (UTC+5:30), and the International Date Line can cause apparent date discrepancies on flights between the Americas and Asia. This calculator handles all of these edge cases correctly.
🌍 Global Coverage Note: The world has 38 distinct time zone offsets (not just 24) because several countries use half-hour and quarter-hour offsets. India (UTC+5:30), Iran (UTC+3:30), Nepal (UTC+5:45), and Sri Lanka (UTC+5:30) are notable examples.
When to Use the Time Zone Calculator
💼 International Business Meetings
Find the overlap of business hours across offices in New York, London, and Singapore. Convert a proposed 9 AM EST meeting time to confirm it is not 3 AM for your Singapore colleagues.
✈️ Flight Arrival Planning
A flight departing Los Angeles at 11 PM and arriving in Tokyo 11 hours later at "10 AM" — but what day? Convert to local time to correctly plan airport pickup and hotel check-in.
📺 Live Events & Broadcasts
Find the local time for live sports events, gaming tournaments, award shows, or product launches broadcast from a different country. Never miss a live event due to a time zone miscalculation.
👥 Remote Team Coordination
Remote teams span multiple continents. Quickly check what time it is for a colleague in Berlin, Bangalore, or Buenos Aires before scheduling a call or sending an urgent message at 2 AM their time.
🏦 Financial Markets
Stock exchanges open at specific local times. Convert NYSE opening (9:30 AM EST) to your local time, or find when the Tokyo Stock Exchange opens in London time for overnight trading strategies.
📞 International Calls
Find a mutually convenient time to call friends or family overseas. Check whether it is a reasonable hour before dialing — a 6 PM call in California is 2 AM in London (not polite).
Time Zone Conversion Formula
All time zone conversions use UTC (Coordinated Universal Time) as the universal reference point:
The Two-Step Conversion Formula
Target Time = UTC Time + Target UTC Offset
Major Time Zone UTC Offsets Reference
| City / Region | Standard Offset | DST Offset |
|---|---|---|
| New York (EST/EDT) | UTC−5 | UTC−4 |
| London (GMT/BST) | UTC+0 | UTC+1 |
| Berlin / Paris (CET/CEST) | UTC+1 | UTC+2 |
| Dubai (GST) | UTC+4 | No DST |
| India (IST) | UTC+5:30 | No DST |
| Singapore / Beijing (CST) | UTC+8 | No DST |
| Tokyo (JST) | UTC+9 | No DST |
| Sydney (AEST/AEDT) | UTC+10 | UTC+11 |
Step-by-Step Calculation Guide
Enter the Source Time
Input the time you want to convert in HH:MM format. Use AM/PM or 24-hour format. Be precise — even a 1-hour error causes missed calls and incorrect flight timing.
Select the Source Time Zone
Choose the time zone where the source time applies. The calculator uses IANA time zone identifiers (e.g., America/New_York) for precise, DST-aware calculations.
Select the Target Time Zone
Choose the destination time zone. The calculator lists zones by city and region for easy lookup. Common zones are at the top; scroll for less common ones.
Check for Date Changes
The result may fall on a different date. A 10 PM Monday in New York converts to 3 AM Tuesday in London. The calculator displays the day change explicitly to prevent confusion.
Account for DST if Applicable
If either the source or destination observes Daylight Saving Time, and the conversion date falls during DST, the calculator automatically applies the adjusted offset. No manual DST adjustment needed.
Worked Examples
Given:
- • Source: 2:00 PM EDT (New York, UTC−4)
- • Target: London (UTC+1 BST in summer)
Solution:
Convert to UTC: 2:00 PM − (−4h) = 6:00 PM UTC
Convert to London BST: 6:00 PM UTC + 1h = 7:00 PM BST
Result: 7:00 PM in London
During summer, when both New York (EDT) and London (BST) are on DST, the difference is 5 hours — not the usual 5 hours in winter when it becomes 5 hours again (EST vs. GMT).
Given:
- • Source: 9:00 AM Monday EDT (UTC−4)
- • Target: Tokyo JST (UTC+9)
Solution:
UTC: 9:00 AM + 4h = 1:00 PM Monday UTC
Tokyo: 1:00 PM + 9h = 10:00 PM Monday
Result: 10:00 PM Monday in Tokyo
Tokyo is 13 hours ahead of New York (during EDT). A 9 AM Monday meeting in New York is 10 PM Monday in Tokyo — late but on the same calendar day.
Given:
- • Participants: New York (UTC−4), London (UTC+1), Singapore (UTC+8)
Solution:
Target: 9 AM UTC as reference
New York: 9 AM − 4h = 5:00 AM (too early)
London: 9 AM + 1h = 10:00 AM (good)
Singapore: 9 AM + 8h = 5:00 PM (acceptable)
Better: Try 1 PM UTC → NY: 9 AM, London: 2 PM, Singapore: 9 PM
1 PM UTC gives New York a 9 AM start (perfect), London a 2 PM meeting (good), and Singapore 9 PM (late but workable). There is no perfect overlap for these three zones.
Given:
- • Source: 3:00 PM IST (India, UTC+5:30)
- • Target: Dubai (UTC+4)
Solution:
UTC: 3:00 PM − 5:30h = 9:30 AM UTC
Dubai: 9:30 AM + 4h = 1:30 PM
Result: 1:30 PM in Dubai
India's UTC+5:30 offset means conversions always involve a 30-minute component. This catches many people off guard when scheduling India-UAE calls.
Given:
- • NYSE Opens: 9:30 AM EST (UTC−5) in winter
- • Target: Singapore (UTC+8)
Solution:
UTC: 9:30 AM + 5h = 2:30 PM UTC
Singapore: 2:30 PM + 8h = 10:30 PM
Result: 10:30 PM in Singapore
Traders in Singapore wanting to trade US equities at NYSE open must stay up until 10:30 PM (or 9:30 PM during EDT/summer when NYSE opens at 9:30 AM EDT = UTC−4).
Common Mistakes to Avoid
Forgetting that DST changes the offset
New York is UTC-5 in winter (EST) but UTC-4 in summer (EDT). A New York–London conversion gives a 5-hour difference in winter but only 4 hours in summer when both observe DST simultaneously.
Assuming all countries observe Daylight Saving Time
China, Japan, India, and most of Africa and Southeast Asia do NOT observe DST. Their offset is constant year-round. When Europe and North America shift clocks, the difference to these zones changes by 1 hour.
Ignoring the date change across the International Date Line
A flight from Los Angeles to Tokyo crosses the date line. Even though the flight is only 11 hours, you arrive the next calendar day.
Using EST (UTC-5) year-round for New York
EST is only valid in winter. From March to November, New York is on EDT (UTC-4). Using the wrong offset by 1 hour can cause missed meetings and flights.
Confusing GMT and BST for London
London is only at UTC+0 (GMT) in winter. In summer (late March to late October), it switches to BST (UTC+1). Always check which offset applies for the specific date you are converting.
Tips and Best Practices
- ✓Always use UTC as the intermediate step. When converting between two non-UTC zones, go through UTC: Source → UTC → Target. This two-step process eliminates offset arithmetic errors.
- ✓Send meeting invites with time zone specified. When scheduling international calls, always include the time zone in the invite (e.g., '3 PM EST / 8 PM GMT'). Let calendar software handle conversion for attendees.
- ✓Be specific about EST vs. EDT (and similar pairs). EST, EDT, GMT, BST, CET, CEST are different offsets. When communicating a time internationally, use the full timezone name or the UTC offset (e.g., UTC-5) to remove ambiguity.
- ✓Use world clocks for ongoing team coordination. For teams that work across 3+ time zones daily, a world clock widget showing all team time zones simultaneously is more practical than manual conversion.
- ✓Check DST transition dates for critical scheduling. DST starts and ends on different dates in North America and Europe (usually 2–3 weeks apart). A meeting scheduled across this transition window may shift by 1 hour unexpectedly.
Related Calculators
Time Duration Calculator
Calculate elapsed time between two moments
Hours Calculator
Calculate hours between two clock times
Time Calculator
Add and subtract time in HH:MM:SS format
Date Calculator
Add or subtract days and months from a date
Day Counter
Count calendar days between two dates
Browse all Time Calculators →
People Also Calculate
Conclusion
The Time Zone Calculator removes one of the most persistent sources of international scheduling confusion. By handling UTC offsets, Daylight Saving Time transitions, non-standard half-hour offsets (like India's UTC+5:30), and date changes automatically, it ensures that your 3 PM in New York really does mean the same moment for everyone you are communicating with.
The golden rule of international scheduling: always communicate times with the UTC offset explicitly stated (e.g., "3 PM UTC-4") and use calendar invitations that automatically convert to each attendee's local time. This eliminates ambiguity and prevents the most common cause of missed international meetings — the DST offset assumption.
Note: Time zone rules change periodically as governments adjust DST dates or permanent offsets. This calculator uses the IANA Time Zone Database, the gold standard for time zone accuracy. Results reflect currently known DST rules, which may change with future legislation.
Frequently Asked Questions
How do time zones work?
The Earth is divided into 24+ time zones defined by UTC offsets. Convert by going through UTC: subtract the source offset to get UTC, then add the target offset.
What is UTC and how is it different from GMT?
UTC is the atomic-clock-based global standard, never adjusted for DST. GMT is the UK civil time zone (UTC+0 in winter). For practical purposes they are equivalent at UTC+0.
What is Daylight Saving Time?
Clocks are advanced 1 hour in summer to shift daylight to evening. This changes the UTC offset for observing countries (e.g., New York goes from UTC-5 to UTC-4).
Which countries don't observe DST?
Most of Asia (China, Japan, India), Africa, and parts of South America do not observe DST. Their UTC offset is constant year-round.
What is the International Date Line?
The IDL runs along the 180° meridian in the Pacific. Crossing it westbound adds a day; eastbound subtracts a day.
How do I schedule a global meeting?
Find a time that falls within business hours for all participants. Convert to UTC first, then check all participants' local equivalents.
Why does India use UTC+5:30?
India uses a single national time zone (IST) with a half-hour offset to better match its geographic midpoint, avoiding the 2-zone split that straight 5-hour zones would require.
People Also Calculate
Calculators visitors commonly use alongside this one.