Time Zone Converter - Convert Time Between Time Zones | Calcoul

Free online time zone converter. Convert time between 30+ world time zones instantly. Perfect for scheduling international meetings, travel planning, and global coordination.

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Time Zone Converter

Free online time zone converter. Convert time between 30+ world time zones instantly. Perfect for scheduling international meetings, travel planning, and global coordination.

Date*

Select the date

Time (HH:MM)*

Enter time in 24-hour format (e.g., 14:30)

From Time Zone*

Select the source time zone

To Time Zone*

Select the target time zone

iAbout This Calculator

The time zone converter is your essential tool for navigating the complex world of global time differences. Whether you're scheduling an international business meeting, coordinating with remote team members across continents, planning a phone call with family overseas, or figuring out when your favorite live stream starts in your local time, this comprehensive converter handles all your time zone conversion needs. Our tool supports 30+ major world time zones, from New York to Tokyo, London to Sydney, covering every major business hub and population center. Unlike basic converters, we show you the complete picture: the exact converted time, which day it falls on (crucial when conversions cross midnight), and the hour difference between zones. Stop doing mental math or getting confused by daylight saving time - let our converter give you accurate, instant results for any time zone pair.

?How to Use

1
Enter the date and time you want to convert using the datetime picker. Select both the date and specific time (hours and minutes).
2
Choose the source time zone ('From') - this is the time zone of your original time. For example, if you're converting a meeting time from New York, select 'Eastern Time (US)'.
3
Select the target time zone ('To') - this is the time zone you want to convert to. For instance, if you need to know what time it is in London, select 'London Time'.
4
Click 'Calculate' to see the converted time with full details including the day of week, time difference in hours, and whether the date changes.
5
Review the breakdown showing both times side by side with their respective time zone abbreviations (EST, GMT, JST, etc.).

fFormula

T_{target} = T_{source} + (UTC_{target} - UTC_{source})

Time zone conversion works by calculating the difference between UTC offsets. Each time zone is defined by its offset from Coordinated Universal Time (UTC). To convert, we add the difference between the target zone's UTC offset and the source zone's UTC offset to the original time. For example, converting from EST (UTC-5) to JST (UTC+9) means adding 14 hours.

T_source: The original time in the source time zone
T_target: The resulting time in the target time zone
UTC_source: The UTC offset of the source time zone
UTC_target: The UTC offset of the target time zone

Examples

New York to London Meeting

Inputs: dateTime: 2026-01-15T09:00, fromTimezone: America/New_York, toTimezone: Europe/London

2:00 PM GMT

A 9:00 AM meeting in New York (EST, UTC-5) is 2:00 PM in London (GMT, UTC+0). London is 5 hours ahead of New York during winter months.

Tokyo to Los Angeles Call

Inputs: dateTime: 2026-01-15T20:00, fromTimezone: Asia/Tokyo, toTimezone: America/Los_Angeles

3:00 AM PST (Previous Day)

An 8:00 PM call in Tokyo (JST, UTC+9) is 3:00 AM in Los Angeles (PST, UTC-8) - the previous day! Tokyo is 17 hours ahead of LA.

Sydney to Berlin Deadline

Inputs: dateTime: 2026-03-20T17:00, fromTimezone: Australia/Sydney, toTimezone: Europe/Berlin

7:00 AM CET

A 5:00 PM deadline in Sydney (AEDT, UTC+11) is 7:00 AM the same day in Berlin (CET, UTC+1). Sydney is 10 hours ahead of Berlin.

India to US East Coast

Inputs: dateTime: 2026-01-15T21:30, fromTimezone: Asia/Kolkata, toTimezone: America/New_York

11:00 AM EST

A 9:30 PM time in India (IST, UTC+5:30) is 11:00 AM the same day in New York (EST, UTC-5). India is 10.5 hours ahead of EST.

Use Cases

Remote Team Coordination

Schedule meetings that work for team members in different countries. Find overlapping business hours between offices in multiple time zones to maximize collaboration without requiring anyone to join at unreasonable hours.

International Business

Coordinate with clients, partners, and suppliers around the world. Know exactly when to send emails for optimal response times, schedule calls during mutual business hours, and meet deadlines in different time zones.

Travel Planning

Plan your travel itinerary with accurate local times. Know what time you'll land, when to expect jet lag, and coordinate with people back home for calls or updates during your trip.

Live Events & Streaming

Never miss a live stream, webinar, product launch, or sports event. Convert the announced time to your local time zone so you can tune in at the right moment.

Family & Friends Overseas

Stay connected with loved ones in different countries. Find the best times to call when both parties are awake, plan video calls for special occasions, and coordinate visits.

Frequently Asked Questions

What is UTC and why is it important?

UTC (Coordinated Universal Time) is the primary time standard by which the world regulates clocks. It's essentially the same as GMT (Greenwich Mean Time) and serves as the reference point for all time zones. Every time zone is defined by its offset from UTC (e.g., EST is UTC-5, JST is UTC+9). Using UTC as a baseline makes time zone conversions consistent and predictable.

How does Daylight Saving Time affect time zone conversions?

DST can change the time difference between zones by 1-2 hours. For example, when the US observes DST but the UK doesn't yet, the difference between New York and London is 4 hours instead of the usual 5. Not all countries observe DST, and those that do may change clocks on different dates. Always verify current offsets for time-sensitive scheduling.

Why do some time zones have 30 or 45 minute offsets?

Most time zones are offset by whole hours from UTC, but some regions chose fractional offsets to better align with solar noon in their area. India (UTC+5:30), Nepal (UTC+5:45), and parts of Australia use these non-standard offsets. Our converter handles these fractional time zones correctly.

What's the largest time difference between any two time zones?

The maximum difference is 26 hours between Line Islands (UTC+14) and Baker Island (UTC-12). However, practically speaking, the largest difference you'll commonly encounter is about 18-19 hours (e.g., between Hawaii and New Zealand). This means the same moment can technically span three different calendar dates across the world!

How do I find the best meeting time for multiple time zones?

Convert the same time from a reference point to all participating time zones. Look for times that fall within 9 AM - 6 PM for most participants. If that's impossible, consider rotating meeting times to share the inconvenience, or record meetings for those who can't attend live.

What is the International Date Line?

The International Date Line (IDL) is an imaginary line running roughly along the 180-degree longitude line in the Pacific Ocean. When you cross it traveling west, you add a day; traveling east, you subtract a day. This is why flights from the US to Asia might 'arrive yesterday' or 'lose a day' - you're crossing the date line.

Do all countries in the same time zone observe the same rules?

No! Countries in the same geographic time zone may observe different rules. For example, Arizona (US) doesn't observe Daylight Saving Time while most other states do. Some countries have changed their time zones for political or economic reasons. Always use specific city/region identifiers rather than just UTC offsets.

How accurate is this converter?

Our converter uses standard UTC offsets for each time zone and provides accurate conversions for typical use cases. For historical dates or future dates where DST rules might change, we recommend double-checking with official sources. The converter is designed for practical, everyday time zone conversions.

Conclusion

The time zone converter eliminates the confusion and mental gymnastics of working across global time zones. Whether you're coordinating a multinational team, planning international travel, or simply trying to catch a live event from another country, this tool gives you instant, accurate conversions between any two time zones. With support for 30+ major zones covering every continent and major business hub, detailed breakdowns showing exact time differences, and clear indication of date changes, you'll never miss another meeting or miscommunicate a deadline due to time zone confusion. Bookmark this tool for all your international time coordination needs.

Pro Tips

*Daylight Saving Time (DST) affects time differences - they can shift by 1-2 hours depending on which zones observe DST and when. Our tool uses standard offsets; check if DST applies to your specific dates.
*When scheduling recurring international meetings, pick a time that falls within business hours (9 AM - 6 PM) for as many participants as possible. Use the converter to test multiple options.
*Remember that date changes can occur when converting across many time zones. A Friday meeting in Tokyo might be Thursday in New York - always check the day!
*For quick mental math: Every 15 degrees of longitude equals roughly 1 hour of time difference. The Earth rotates 360 degrees in 24 hours.
*When traveling, convert your flight arrival time to your home time zone to understand the jet lag impact and plan your first day accordingly.

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