🕑 Live Current Time — Select Any Zone
Your Local Time
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UTC / GMT
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UTC+0
Quick City Select — From Zone
Select the time zone you know
Please select a valid time zone.
Enter time in 24-hour format
Quick City Select — To Zone
Select the target time zone
Please select a valid time zone.
Date matters for DST accuracy — defaults to today
Find the best hours for a meeting between two time zones. Shows which standard working hours (9 AM–6 PM) overlap.
First participant’s time zone
Second participant’s time zone
Converted Time
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⚠️ DST Notice: Daylight saving time is handled automatically using the IANA time zone database via your browser’s built-in Intl API. Results are accurate for the selected date. DST rules change periodically by law — ensure your browser is up to date for the most accurate results. Verify critical times independently for scheduling important events.
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Sources & Methodology
All time zone conversions use the IANA Time Zone Database (tzdata) via the browser’s built-in Intl.DateTimeFormat API. DST rules are handled automatically. UTC offsets are calculated precisely at the moment of conversion, correctly reflecting any daylight saving transitions.
IANA Time Zone Database (tzdata)
The authoritative global database of time zone rules. Maintained by Paul Eggert and the IANA, it covers all countries' time zone history, DST transition dates, and UTC offsets. Updated continuously as countries change their DST rules. Modern browsers implement tzdata in the Intl API used by this calculator.
BIPM — International Bureau of Weights and Measures, UTC
Coordinated Universal Time (UTC) is maintained by the International Bureau of Weights and Measures (BIPM) using a weighted average of 400+ atomic clocks worldwide. UTC is the world’s primary time standard against which all time zones are defined. This calculator uses UTC internally as the conversion base.
ECMA-262 / Intl.DateTimeFormat API
The JavaScript Intl.DateTimeFormat API used in this calculator is standardised by ECMA-262. It gives access to the host system’s tzdata implementation, ensuring DST rules are applied correctly for any date, including historical and future transitions, without manual maintenance.
Methodology — DST-Aware Conversion:
Step 1: Parse input time and combine with selected date (YYYY-MM-DD + HH:MM) Step 2: Interpret that datetime in the source timezone using Intl.DateTimeFormat Step 3: Get UTC epoch milliseconds for that moment Step 4: Format epoch in target timezone using Intl.DateTimeFormat with timeZone option UTC Offset = (Local time) − (UTC time) at the exact moment of conversion DST is applied automatically because the IANA database is called at the specific date+time, not using a static offset. This correctly handles spring-forward and fall-back transitions, half-hour offsets (India, Iran, Afghanistan), and quarter-hour offsets (Nepal, Chatham Islands).
Step 1: Parse input time and combine with selected date (YYYY-MM-DD + HH:MM) Step 2: Interpret that datetime in the source timezone using Intl.DateTimeFormat Step 3: Get UTC epoch milliseconds for that moment Step 4: Format epoch in target timezone using Intl.DateTimeFormat with timeZone option UTC Offset = (Local time) − (UTC time) at the exact moment of conversion DST is applied automatically because the IANA database is called at the specific date+time, not using a static offset. This correctly handles spring-forward and fall-back transitions, half-hour offsets (India, Iran, Afghanistan), and quarter-hour offsets (Nepal, Chatham Islands).
Last reviewed: April 2026
Time Zone Conversion Guide — Everything You Need to Know
Time zones exist because the Earth rotates 360° every 24 hours, meaning different parts of the world experience day and night at different times. The world is divided into 24 primary time zones, each theoretically 15° of longitude wide, though in practice country borders, economic ties, and political decisions make time zone boundaries irregular. Understanding time zones is essential for international business, travel, remote work coordination, global streaming, and scheduling.
UTC and GMT — What is the Difference?
UTC (Coordinated Universal Time) is the world’s primary time standard, maintained by approximately 400 atomic clocks worldwide and coordinated by the BIPM. It is the international benchmark against which all time zones are defined. UTC does not observe daylight saving time and never changes — it is constant. GMT (Greenwich Mean Time) is the mean solar time at the Royal Observatory in Greenwich, London. While UTC and GMT show the same time (both are UTC±0), they are technically different: GMT is a time zone, UTC is a time standard. Modern applications and systems use UTC as the reference. GMT is still used as the official time zone designation for the UK in winter, Ireland, Iceland, and several West African countries.
UTC Offset Reference Table — Major Time Zones
| UTC Offset | Name / Abbreviation | Example Locations | DST? |
|---|---|---|---|
| UTC−12 | IDLW | Baker Island, Howland Island | No |
| UTC−8 | PST (Pacific Standard) | Los Angeles, Seattle, Vancouver | Yes (PDT UTC−7) |
| UTC−7 | MST (Mountain Standard) | Denver, Phoenix (year-round) | MDT UTC−6; AZ no DST |
| UTC−6 | CST (Central Standard) | Chicago, Mexico City, Dallas | Yes (CDT UTC−5) |
| UTC−5 | EST (Eastern Standard) | New York, Toronto, Miami | Yes (EDT UTC−4) |
| UTC−3 | BRT (Brasilia) | São Paulo, Rio de Janeiro | Some states yes |
| UTC+0 | GMT / WET / UTC | London (winter), Lisbon (winter), Accra | UK yes (BST UTC+1) |
| UTC+1 | CET (Central European) | Paris, Berlin, Rome, Madrid | Yes (CEST UTC+2) |
| UTC+2 | EET / CAT | Cairo, Johannesburg, Athens (winter) | Some yes |
| UTC+3 | MSK / EAT | Moscow, Nairobi, Riyadh | No (Russia abolished 2014) |
| UTC+4 | GST | Dubai, Abu Dhabi | No |
| UTC+5 | PKT (Pakistan Standard) | Karachi, Islamabad, Lahore | No |
| UTC+5:30 | IST (India Standard) | Mumbai, Delhi, Bangalore, Kolkata | No |
| UTC+5:45 | NPT (Nepal) | Kathmandu | No |
| UTC+6 | BST / BTT | Dhaka, Almaty | No |
| UTC+7 | WIB / ICT | Bangkok, Jakarta, Ho Chi Minh City | No |
| UTC+8 | CST (China) / SGT | Beijing, Shanghai, Singapore, Kuala Lumpur | No |
| UTC+9 | JST / KST | Tokyo, Seoul | No |
| UTC+10 | AEST | Sydney, Melbourne (winter) | Yes (AEDT UTC+11) |
| UTC+12 | NZST | Auckland (winter) | Yes (NZDT UTC+13) |
Daylight Saving Time (DST) — How It Works
Daylight saving time (DST) is the practice of setting clocks forward by one hour in spring to shift daylight to evening hours, then setting them back in autumn. Approximately 70 countries observe DST, but the dates differ:
- United States & Canada: Clocks spring forward the second Sunday of March, fall back first Sunday of November (since 2007)
- European Union: Last Sunday of March (spring forward), last Sunday of October (fall back)
- Australia & New Zealand: Southern hemisphere — spring forward in October, fall back in April
- No DST: China, Japan, India, Pakistan, most of Asia, Russia (abolished 2014), most of Africa, most Middle East
⚠️ Critical DST scheduling trap: When the US switches DST clocks (March/November) while the EU hasn’t yet (or vice versa), the time difference between New York and London temporarily changes from 5 hours to 4 or 6 hours for about 2–3 weeks. This catches international schedulers off guard. Always verify time differences around DST transition dates. This calculator handles this automatically — just select the correct date.
Common Time Differences — Quick Reference
| From → To | Winter (Standard) | Summer (Daylight) | Notes |
|---|---|---|---|
| New York → London | +5 hours | +4 or +5 hours | Varies during DST transitions |
| New York → Paris | +6 hours | +5 or +6 hours | Varies during DST transitions |
| New York → Dubai | +9 hours | +8 hours | Dubai has no DST |
| New York → India (IST) | +10.5 hours | +9.5 hours | India has no DST |
| New York → Tokyo | +14 hours | +13 hours | Japan has no DST |
| Los Angeles → New York | −3 hours | −3 hours | Always 3 hours; both observe DST |
| London → Karachi | +5 hours | +4 hours | Pakistan has no DST |
| London → India | +5.5 hours | +4.5 hours | India has no DST; half-hour offset |
| London → Singapore | +8 hours | +7 hours | Singapore has no DST |
| London → Sydney | +10 or +11 hours | +9 hours | Both observe DST (opposite hemispheres) |
Frequently Asked Questions
UTC (Coordinated Universal Time) is the world’s primary time standard based on atomic clocks. GMT (Greenwich Mean Time) is the mean solar time at Greenwich, London. Both show the same time (UTC±0 / GMT), but UTC is a standard and GMT is a time zone. Modern systems use UTC. GMT is the official designation for UK winter time and several West African countries.
EST (Eastern Standard Time) is UTC−5. Add 5 hours to EST to get UTC. Example: 3:00 PM EST = 8:00 PM UTC. During summer (EDT, Eastern Daylight Time), the offset is UTC−4, so add 4 hours instead.
London is GMT (UTC+0) in winter (late October to late March) and BST — British Summer Time (UTC+1) in summer. London is 5 hours ahead of New York in winter, 4–5 hours ahead in summer (the difference shifts during the 2–3 weeks when US and UK change clocks on different dates).
PST is UTC−8, EST is UTC−5. EST is 3 hours ahead of PST always. Add 3 hours to PST to get EST. Example: 10 AM PST = 1 PM EST. During DST both switch simultaneously (PDT UTC−7, EDT UTC−4), maintaining the same 3-hour gap.
No. India Standard Time (IST) is UTC+5:30 year-round. India does not observe DST. This means when the US or UK switches clocks for DST, the time difference between those countries and India changes by 1 hour for part of the year.
Tokyo (JST, UTC+9) is 14 hours ahead of New York (EST, UTC−5) in winter, and 13 hours ahead in summer (EDT, UTC−4). Japan does not observe DST. A 9 AM Monday meeting in New York would be 11 PM Monday in Tokyo (or 10 PM in US summer).
The US springs forward clocks on the second Sunday of March, while the EU changes on the last Sunday of March. For the 2–3 weeks in between, the US has already moved to daylight time but the UK hasn’t yet, making the transatlantic difference 4 hours instead of the usual 5. This catches many people off guard. Always verify around these dates — this calculator handles it automatically using the selected date.
IST (UTC+5:30) is 10 hours 30 minutes ahead of EST (UTC−5) in winter, and 9 hours 30 minutes ahead of EDT (UTC−4) in summer. So noon EST = 10:30 PM IST. For morning EST, add 10.5 hours (winter): 9 AM EST = 7:30 PM IST.
Major countries without DST: China, Japan, India, Pakistan, most of Southeast Asia, Russia (abolished 2014), most of Africa, Saudi Arabia, UAE, Qatar, most Middle East. Within the US, Arizona (except Navajo Nation) and Hawaii do not observe DST. Most of the world’s population actually lives in countries without DST.
Use the Meeting Planner tab above. Select both time zones and the tool shows which hours overlap within standard working hours (9 AM–6 PM). For example: US East Coast (ET) and UK have overlap 2–5 PM ET (7–10 PM UK) in winter. ET and India overlap barely at 7:30–8:30 PM EST (6–7 AM IST next day).
Karachi, Pakistan is in Pakistan Standard Time (PKT), which is UTC+5. Pakistan does not observe daylight saving time, so PKT is fixed at UTC+5 year-round. Karachi is 5 hours ahead of London (GMT/UTC+0) in winter, and 4 hours ahead when the UK is on BST in summer.
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