Timezone Converter

Convert any date and time between world timezones. Includes a live clock mode and multi-zone comparison.

Timezone Converter

UTCUTC+00:00source
Sat, Apr 11, 2026
09:45:00
New York (ET)UTC-04:00
Sat, Apr 11, 2026
05:45:00
London (GMT/BST)UTC+01:00
Sat, Apr 11, 2026
10:45:00
Mumbai (IST)UTC+05:30
Sat, Apr 11, 2026
15:15:00
Tokyo (JST)UTC+09:00
Sat, Apr 11, 2026
18:45:00

How to Use

1

Enter the date and time

Select the date and time to convert. Date matters since timezone shifts can change the calendar day.

2

Select the source timezone

Choose the timezone the input time belongs to from the IANA timezone list.

3

Add target timezones

Pick one or more destination timezones to see the equivalent time in each location.

4

Use live clock mode

Enable live clock to see real-time current time across all selected zones simultaneously.

Understanding Timezones

The world is divided into 24 primary time zones, each offset from Coordinated Universal Time (UTC). Time zones are critical for international scheduling, software development, and global communication. This tool converts times across all major IANA time zones.

Real-World Examples & Use Cases

International Meeting and Call Scheduling

Scheduling calls across multiple timezones requires knowing that when it's 9 AM in New York, it is 2 PM in London, 3 PM in Berlin, 10 PM in Tokyo, and only 6 AM in Los Angeles. Choosing a meeting time that works for all participants requires knowing everyone's local time simultaneously. Sales teams scheduling demos with international prospects, engineering teams coordinating daily stand-ups with offshore developers, and executives scheduling board calls with international directors all depend on timezone converters to find workable meeting times.

Software Development and API Timestamp Handling

Developers storing and displaying timestamps in web applications must handle timezone conversion correctly to avoid displaying incorrect times to users. A database-stored UTC timestamp '2024-03-15 14:00:00 UTC' should display as '10:00 AM EDT' for New York users and '11:00 PM JST' for Tokyo users. Understanding the offset and DST rules for each timezone helps developers write correct conversion code. Verifying that a timestamp displays correctly across multiple timezones requires a reliable converter for testing.

Watching Live Events and Broadcasts Internationally

Sports events, live streams, award shows, and webinars are announced in one timezone but watched globally. A Formula 1 race scheduled at 2:00 PM local circuit time needs to be converted by fans worldwide to know when to tune in. Concert livestreams, live financial market openings, and scheduled political addresses are all announced in specific timezones that international audiences must convert. Getting the timezone wrong means missing a live event entirely.

Travel Planning and Jet Lag Management

International travelers moving across multiple timezones plan their sleep and activity schedules around destination local time. Calculating arrival time in a destination timezone from a departure time requires knowing the UTC offset difference and accounting for Daylight Saving Time transitions that may occur during the journey. Flight schedulers and travel apps display departure and arrival times in local timezones — understanding these conversions helps travelers plan connections, ground transportation, and hotel check-in times accurately.

How It Works

Timezone conversion mathematics: Concept: Every timezone offset is expressed relative to UTC: HKT (Hong Kong): UTC+8 = UTC + 8 hours EST (Eastern Standard): UTC-5 = UTC - 5 hours IST (India): UTC+5:30 = UTC + 5 hours 30 minutes Conversion formula: UTC_time = local_time - UTC_offset target_time = UTC_time + target_UTC_offset Example: 3:00 PM EST to JST EST = UTC-5: UTC = 3:00 PM + 5h = 8:00 PM UTC JST = UTC+9: JST = 8:00 PM UTC + 9h = 5:00 AM JST next day Daylight Saving Time (DST): Not all regions observe DST. When DST is active: US Eastern: EST (UTC-5) becomes EDT (UTC-4) in summer UK: GMT (UTC+0) becomes BST (UTC+1) in summer DST transitions complicate conversions — the IANA timezone database stores all historical DST rules for each zone JavaScript implementation: const date = new Date(inputDateTimeString); const target = date.toLocaleString('en-US', { timeZone: 'Asia/Tokyo', dateStyle: 'short', timeStyle: 'short' }); // Or use Intl.DateTimeFormat for more control

Frequently Asked Questions

What is UTC and how does it relate to timezones?▼
UTC (Coordinated Universal Time) is the primary international time standard that all other timezones are defined relative to. It is not a timezone itself but a time scale maintained by atomic clocks. All timezone offsets are expressed as UTC+ or UTC- hours/minutes. UTC is the successor to GMT (Greenwich Mean Time) and is essentially equivalent for most practical purposes, though they differ in precise technical definition.
What is Daylight Saving Time and which countries observe it?▼
Daylight Saving Time (DST) is the practice of moving clocks one hour forward in spring and back in autumn to shift daylight hours later in the day during summer. Countries observing DST include the US, Canada, most of Europe, Australia, Brazil, and others. Countries that do NOT observe DST include Japan, China, India, most of Africa, the Middle East, and others. DST transitions different countries observe happen on different calendar dates, making cross-timezone conversions during transition periods complex.
Why do some timezone offsets have 30-minute or 45-minute increments?▼
Most timezones use whole-hour UTC offsets, but about 30 key timezones use half-hour or 45-minute offsets. India Standard Time (IST) is UTC+5:30. Nepal Time is UTC+5:45. Iran Standard Time is UTC+3:30. Australia Central Standard Time is UTC+9:30. These non-standard offsets reflect geographic, political, or historical decisions made when timezones were formally defined for those regions.
What is the IANA timezone database?▼
The IANA Timezone Database (also called the Olson database or tz database) is the authoritative, freely available database of all world timezones, maintained by IANA. It records all historical timezone transitions, DST rules, and current UTC offsets for every region in the world using city-based identifiers (e.g. America/New_York, Asia/Tokyo). All operating systems, programming languages, and time conversion tools use this database as their source of truth for timezone rules.
Can a timezone conversion change the calendar date?▼
Yes. A time on one side of midnight in the source timezone may fall on the previous or next calendar day in the target timezone. Example: midnight (00:00) UTC on January 15 is 9:00 AM JST on January 15 but 7:00 PM EST on January 14. International collaborators must always specify both the time AND the date when scheduling across timezones to avoid day-boundary confusion.

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