Time Zone Calculator UK 2025 - GMT BST World Time Converter
Convert UK time (GMT/BST) to world time zones instantly with our comprehensive time zone calculator. Essential for international business calls, travel planning, remote work coordination, and scheduling global meetings. Features live world clock, meeting planner, DST tracker, and jet lag calculator - all updated for 2025.
Live World Clock
Current time in major cities around the world, updated live. All times shown relative to UK time.
Add City to Track
🔄 UK Time Zone Converter
Convert any UK time to another timezone quickly and accurately.
📅 International Meeting Planner
Find the best time for meetings with participants across multiple time zones. See who's in working hours.
📊 Optimal UK Meeting Windows
UK Time
Best For
Notes
7:00-9:00
Asia/Australia
End of Asia day, morning in Australia
14:00-16:00
UK + USA East
Afternoon UK, morning USA East Coast
17:00-18:00
UK + USA (all)
End UK day, USA full working hours
19:00-21:00
USA West Coast
UK evening, morning in California
🕐 UK Daylight Saving Time Tracker 2025
Track when clocks change in the UK and worldwide. Never miss a DST transition again.
UK Clock Changes 2025
🌸 Sun 30 March 2025
Clocks go FORWARD at 1:00am → 2:00am
BST begins (UTC+1). Lose 1 hour of sleep. Evenings become lighter.
🍂 Sun 26 October 2025
Clocks go BACK at 2:00am → 1:00am
GMT returns (UTC+0). Gain 1 hour of sleep. Evenings become darker.
Global DST Changes 2025
Country/Region
Spring Forward
Fall Back
Notes
🇬🇧 UK
30 March
26 October
Last Sunday of month
🇺🇸 USA
9 March
2 November
2nd Sun Mar, 1st Sun Nov
🇪🇺 EU
30 March
26 October
Same as UK
🇦🇺 Australia
5 October
6 April
Opposite to Northern Hemisphere
🇳🇿 New Zealand
28 September
6 April
Opposite to Northern Hemisphere
⚠️ DST Transition Warning Periods
During late March and early November, UK and USA clock changes happen on different dates. This temporarily changes time differences by 1 hour. Always double-check with a timezone converter during these periods!
✈️ Jet Lag Recovery Calculator
Calculate how long it takes to recover from jet lag based on your travel destination and direction.
The World Clock tab displays live times for major cities around the world, all updating in real-time. The UK time is prominently highlighted, with other cities showing their local time and the offset from UK. You can add additional cities to track using the dropdown menu.
Time Converter
Use the Time Converter to convert any UK time to another timezone. Simply enter the UK time, select your target city, and click convert. The result shows both times clearly, including whether the date changes (useful for large timezone differences).
Meeting Planner
The Meeting Planner helps you find suitable times for international meetings. Select the locations of your participants, enter your proposed UK meeting time, and the tool shows each location's local time with colour coding: green for normal working hours (9am-5pm), amber for early/late (7am-9am, 5pm-7pm), and red for outside working hours.
DST Tracker
The DST Tracker keeps you informed about when clocks change in the UK and worldwide. It shows the current UK timezone (GMT or BST), countdown to the next clock change, and a comparison table of DST dates across different countries to avoid scheduling confusion.
Jet Lag Calculator
Flying abroad? The Jet Lag Calculator estimates your recovery time based on the number of timezone crossed and direction of travel. Eastward travel (to Asia/Australia) typically causes more severe jet lag than westward travel (to Americas). The tool provides personalised recovery tips based on your destination.
🌍 Understanding UK Time Zones in 2025
GMT vs BST - UK Time Explained
The United Kingdom uses two time systems throughout the year: GMT (Greenwich Mean Time, UTC+0) from late October to late March, and BST (British Summer Time, UTC+1) from late March to late October. GMT is the baseline timezone for the entire world - all other timezones are expressed as hours ahead (+) or behind (-) GMT.
The transition dates for 2025 are:
30 March 2025 (1:00am): Clocks go FORWARD to 2:00am - BST begins, we lose 1 hour sleep
26 October 2025 (2:00am): Clocks go BACK to 1:00am - BST ends, we gain 1 hour sleep
Why Does Greenwich Set World Time?
Greenwich Mean Time (GMT) was established in 1675 when the Royal Observatory was founded in Greenwich, London. GMT became the world's time standard because Britain's naval and commercial dominance required a reference point for navigation. The Prime Meridian (0° longitude) runs through Greenwich, making GMT the baseline from which all other timezones are calculated. In 1884, the International Meridian Conference formally adopted Greenwich as the zero point for timekeeping worldwide.
Common Time Zone Differences from UK
City/Region
Time Zone
Difference from UK
Example (3pm London)
New York, USA
EST (UTC-5)
5 hours behind
10:00am
Los Angeles, USA
PST (UTC-8)
8 hours behind
7:00am
Paris, France
CET (UTC+1)
1 hour ahead
4:00pm
Dubai, UAE
GST (UTC+4)
4 hours ahead
7:00pm
Mumbai, India
IST (UTC+5:30)
5.5 hours ahead
8:30pm
Singapore
SGT (UTC+8)
8 hours ahead
11:00pm
Tokyo, Japan
JST (UTC+9)
9 hours ahead
12:00am (next day)
Sydney, Australia
AEDT (UTC+10)
10 hours ahead
1:00am (next day)
The Challenge of Daylight Saving Time
Different countries change clocks on different dates, creating temporary timezone confusion:
UK/EU: Last Sunday in March (forward), last Sunday in October (back)
USA: Second Sunday in March (forward), first Sunday in November (back)
Australia/NZ: Opposite dates (they have opposite seasons!)
Some countries don't observe DST at all: Japan, China, India, Singapore, most of Africa
For 2-3 weeks each spring and autumn, time differences between UK and USA change by 1 hour due to misaligned clock change dates. Always double-check timezone converters during late March, late October, and early November.
How Many Time Zones Exist?
There are 38 different time zones worldwide, ranging from UTC-12 to UTC+14. It's not a simple 24 because some countries use half-hour (India at UTC+5:30, Iran at UTC+3:30) and even 45-minute offsets (Nepal at UTC+5:45). Some interesting facts:
Kiribati: Uses UTC+14, making them first to see each new day
France: Has 12 time zones (due to overseas territories)
📅 Best Times for International Meetings from UK
UK-USA Meetings
The optimal window for UK-USA calls is 2pm-5pm GMT/BST. This catches USA East Coast at 9am-12pm when people are fresh, and USA West Coast at 6am-9am (early but workable). Avoid 9am UK (4am PST - too early for West Coast) and after 6pm UK (after 1pm EST - USA lunch break or end of day).
UK-Europe Meetings
Europe is the easiest region for UK businesses. Most of continental Europe is just 1-2 hours ahead (CET/CEST), making any time between 9am-5pm UK suitable. Just remember that Southern European countries (Spain, Italy, Greece) often have later lunch breaks (2pm-4pm) and work later into the evening.
UK-Asia Meetings
Asia presents the biggest challenge due to 5-9 hour differences:
7am-9am UK: Catches end of Asia's working day (3pm-5pm Singapore/Tokyo)
6pm-8pm UK: Catches start of Asia's day (very early morning there)
Best compromise: 8am UK = 4pm Singapore/Tokyo (end of their day, start of UK day)
UK-Australia Meetings
With 10-11 hours difference, UK-Australia meetings require sacrifice from one side:
7am UK = 5pm-6pm Sydney: Catches end of Australia's day (requires early UK start)
8pm UK = 6am-7am Sydney: Catches start of Australia's day (requires late UK evening)
Solution: Rotate meeting times monthly to share inconvenience fairly
Global Team Meetings (All Continents)
If you need to include participants from Americas, Europe, AND Asia, there is no perfect time. Options:
Hold two sessions: One for UK+Americas, one for UK+Asia
Use async tools: Loom, Notion, Slack for updates that don't need live discussion
💡 Expert Tips for Managing UK Time Zones
1. Always Specify GMT or BST in Communications
When scheduling meetings or calls with international colleagues, never write just "3pm" - always specify "3pm GMT" or "3pm BST". Different countries interpret times in their local timezone, which can lead to missed meetings. Include timezone information in email signatures and calendar invites.
2. Use Automated Timezone Tools
Google Calendar automatically converts meeting times to each participant's local timezone. Calendly detects visitor timezones and displays available slots in their local time. World Time Buddy shows multiple timezones side-by-side. These tools prevent human error in timezone calculations.
3. Be Aware of DST Transition Periods
For 2-3 weeks each spring and autumn, UK and USA clock changes happen on different dates. During late March, early November, and late October, time differences shift by one hour. Always double-check timezone converters during these transition periods.
4. Schedule UK-USA Meetings in UK Afternoon
The sweet spot for UK-USA calls is 2pm-5pm GMT. This catches USA East Coast morning (9am-12pm EST) when people are fresh, while still being reasonable UK working hours. Avoid 9am UK (4am PST - too early for West Coast).
5. Rotate Inconvenient Times for Global Teams
For regular UK-Asia or UK-Australia meetings where no time is convenient for everyone, rotate meeting times monthly. One month: 8am UK (evening Asia), next month: 8pm UK (morning Asia). This shares the inconvenience fairly.
6. Record Meetings for Asynchronous Viewing
When timezone differences make live attendance impossible, record meetings using Zoom, Teams, or Loom. Share recordings immediately after meetings so colleagues in incompatible timezones can watch at convenient times.
7. Build Timezone Awareness into Your Daily Routine
Install world clock widgets on your phone/computer showing key timezones you work with regularly. Before sending messages to international colleagues, check their local time - don't send urgent requests at 11pm their time.
8. Plan International Travel with Timezone Calculators
When booking flights or planning itineraries, use timezone converters to avoid confusion. A flight leaving London at 10pm that arrives in New York at 1am (local time) actually involves a 7-hour flight plus 5-hour timezone change. Understanding this helps with jet lag planning.
⚠️ Common Time Zone Mistakes to Avoid
1. Forgetting UK Switches Between GMT and BST
Mistake: Assuming UK is always GMT (UTC+0) year-round. Reality: UK uses BST (UTC+1) from late March to late October, changing the time difference with other countries by 1 hour. Fix: Always check current UK timezone - it's GMT (winter) or BST (summer).
2. Not Accounting for Different DST Change Dates
Mistake: Assuming all countries change clocks on the same date. Reality: UK changes last Sunday in March/October, USA changes second Sunday in March, first Sunday in November. This creates 2-3 week periods where time differences are unusual.
3. Scheduling Meetings Outside Working Hours
Mistake: Booking a 9am UK meeting without realizing it's 4am PST or midnight in Singapore. Fix: Before sending calendar invites, convert the time to all participants' local timezones and verify it falls within reasonable working hours (8am-6pm local time).
4. Relying on Mental Timezone Math
Mistake: Trying to calculate "New York is 5 hours behind, so 3pm UK is 10am NY" in your head, especially during DST transitions. Fix: Always use timezone converter tools. Don't trust mental calculations for important meetings.
5. Forgetting Date Changes Across Timezones
Mistake: Scheduling "Monday 9am Singapore time" from UK without realizing it's Sunday evening in UK. Fix: Always specify both date and time with timezone: "Monday 9am SGT (Sunday 11pm GMT)" to make the date difference explicit.
6. Using Outdated Timezone Information
Mistake: Assuming timezone rules never change. Reality: Countries occasionally change timezone policies - some abolish DST, others adjust offsets. Fix: Use up-to-date timezone databases and online tools rather than relying on memory.
❓ Frequently Asked Questions
UK to USA time differences in 2025: New York (EST) is 5 hours behind UK, Los Angeles (PST) is 8 hours behind UK, Chicago (CST) is 6 hours behind. When it's 3pm in London, it's 10am in New York, 7am in Los Angeles. Both countries observe daylight saving time but on different dates - UK switches last Sunday in March/October, USA switches second Sunday in March, first Sunday in November. This creates brief 2-3 week periods where time differences change by 1 hour.
The UK uses GMT (Greenwich Mean Time, UTC+0) from last Sunday in October to last Sunday in March. From last Sunday in March to last Sunday in October, the UK uses BST (British Summer Time, UTC+1). In 2025, BST starts 30 March at 1am (clocks forward) and ends 26 October at 2am (clocks back). BST gives longer evening daylight in summer. GMT is also called UTC (Coordinated Universal Time) - they're effectively the same for UK purposes.
UK clock changes 2025: (1) Sunday 30 March 2025 at 1:00am - clocks go FORWARD to 2:00am (start BST, lose 1 hour). (2) Sunday 26 October 2025 at 2:00am - clocks go BACK to 1:00am (end BST, gain 1 hour). Memory aid: Spring forward, Fall back. Digital devices (phones, computers) update automatically. Analog clocks need manual adjustment. EU countries still change clocks on the same dates as UK.
For UK international meetings: (1) Use this converter to find overlapping working hours. (2) Best UK meeting times: 2pm-4pm UK works for USA East Coast (9am-11am EST), Europe (3pm-5pm CET), and Asia Pacific next morning. (3) Avoid: 9am UK (too early for USA, past work hours in Asia), 5pm+ UK (evening in Europe, late night in Asia). (4) Always specify timezone in invites: '3pm GMT' not just '3pm'. (5) Remember daylight saving changes differ between countries.
London uses GMT (Greenwich Mean Time, UTC+0) in winter and BST (British Summer Time, UTC+1) in summer. GMT is the reference timezone for the world - all other timezones are calculated as +/- hours from GMT. London is at 0° longitude (Prime Meridian), which is why GMT is based here. The entire UK uses the same timezone - there are no regional timezone differences like in USA, Canada, Australia, or Russia. Northern Ireland, Scotland, Wales, England all observe GMT/BST simultaneously.
There are 38 different time zones worldwide, ranging from UTC-12 to UTC+14 (not a simple 24 because some countries use half-hour and quarter-hour offsets). Major time zones from UK perspective: USA has 4 main zones, Europe mostly uses CET (UTC+1), Russia has 11 time zones, China uses 1 timezone nationwide despite spanning 5 geographical zones, India uses IST (UTC+5:30) with half-hour offset. Some territories like Kiribati use UTC+14, making them first to see each new day.
UK jet lag prevention tips: (1) Eastward travel (Europe/Asia): Go to bed 30-60 minutes earlier for 3 days before departure, seek bright light in morning, avoid afternoon naps. (2) Westward travel (Americas): Stay up 30-60 minutes later for 3 days before departure, seek bright light in evening, take short afternoon naps. (3) On flight: Set watch to destination time immediately, sleep when it's night there. (4) On arrival: Force yourself to stay awake until local bedtime, get sunlight exposure, eat meals at local times. Recovery time: roughly 1 day per timezone crossed.
Best timezone converters for UK: (1) This UK Calculator timezone tool - simple GMT/BST conversions for common destinations. (2) World Time Buddy - visual slider showing multiple timezones simultaneously, perfect for finding meeting overlaps. (3) timeanddate.com - comprehensive historical and future timezone data including DST changes. (4) Google Calendar - automatically converts meeting times to each participant's local timezone. (5) Calendly - detects visitor timezones and shows your availability in their local time.
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Written by Daniel Whitmore
BSc Computer Science, Former IBM Global Services Consultant
Daniel has 18 years of experience managing international technology projects across 4 continents. He has coordinated teams spanning UK, USA, India, and Australia, developing expertise in timezone management, asynchronous collaboration, and international meeting scheduling. Daniel now consults on remote work practices and global team coordination.
✓ Expert Reviewed — This calculator is reviewed by our team of financial experts and updated regularly with the latest UK tax rates and regulations. Last verified: January 2026.
Last updated: January 2026 | Verified with latest UK rates