Timezone Converter

Timezone Converter for the UK — How It Works

The UK operates on Greenwich Mean Time (GMT, UTC+0) in winter and British Summer Time (BST, UTC+1) in summer. Clocks go forward one hour on the last Sunday of March and back on the last Sunday of October. This single-hour shift catches out thousands of UK professionals every year when scheduling international calls — particularly with the US and Australia, which change clocks on different dates, creating brief windows where the usual time difference shifts by an extra hour.

Key Time Differences from London

• London → New York: GMT −5h (EST) in winter, −4h (EDT) in summer. When the UK is on GMT and the US is on EST, New York is 5 hours behind. In early spring (when the US switches before the UK), the gap briefly becomes 4 hours.
• London → Los Angeles: 8 hours behind London in winter, 7–8 hours in summer depending on DST crossover timing.
• London → Sydney: Sydney is UTC+10 (AEST) or UTC+11 (AEDT) in Australian summer. In UK winter, Sydney is 11 hours ahead; in UK summer it can drop to 9 hours as the two countries' DST cycles partially offset each other.
• London → Dubai: Dubai is UTC+4 all year — no DST. London is 4 hours behind Dubai in winter and 3 hours behind in summer (BST).
• London → Tokyo: Tokyo is UTC+9, no DST. London is 9 hours behind in winter, 8 hours behind in summer.
• London → Singapore: UTC+8, no DST. 8 hours ahead of GMT, 7 hours ahead of BST.

DST Changeover Dates — UK 2025 & 2026

UK clocks change twice a year under the EU-derived system still retained post-Brexit:

• Spring forward 2025: Sunday 30 March at 01:00 → 02:00 (GMT to BST)
• Fall back 2025: Sunday 26 October at 02:00 → 01:00 (BST to GMT)
• Spring forward 2026: Sunday 29 March at 01:00 → 02:00
• Fall back 2026: Sunday 25 October at 02:00 → 01:00

The US switches on the second Sunday of March and first Sunday of November. This creates a 2–3 week window each spring and autumn where the London–New York difference is one hour different from normal. Always verify with a live converter during these windows.

Best Time to Call — Top 5 UK International Routes

• London → New York: 14:00–18:00 GMT/BST. NY is 9–10 AM, fully in morning hours. Avoid before 14:00 (NY still before 9 AM) and after 22:00 GMT (NY past 5 PM).
• London → Los Angeles: 17:00–20:00 GMT/BST is optimal. LA is 9 AM–12 PM, ideal for morning meetings. Before 17:00 GMT, LA is pre-work; after 20:00, LA is still in business hours but London is evening.
• London → Toronto: Same as New York (Toronto/New York share Eastern Time). 14:00–18:00 GMT.
• London → Dubai: 06:00–14:00 GMT (winter) or 06:00–15:00 BST (summer). Dubai starts at 8 AM while London is at 4–5 AM in winter — so the sweet spot for both parties is 09:00–13:00 London time, when Dubai is 13:00–17:00.
• London → Sydney: This is the hardest route — the gap is 10–11 hours. The only viable overlap is 08:00–09:00 London (18:00–19:00 Sydney) or 17:00–18:00 London (03:00–04:00 Sydney, too early). Best option: 08:00–09:30 GMT, catching Sydney just before their end-of-day.

Frequently Asked Questions

What is the time difference between London and New York?

London is typically 5 hours ahead of New York in winter (GMT vs EST) and 4–5 hours ahead in summer depending on DST changeover timing. When London is on BST and New York is on EDT, the difference is exactly 5 hours. During the 2–3 week window in March when the US has already switched but the UK has not yet, the difference is 4 hours.

Does the UK observe daylight saving time?

Yes. The UK observes British Summer Time (BST, UTC+1) from the last Sunday in March to the last Sunday in October. Outside those dates, the UK is on GMT (UTC+0). The time change occurs at 1 AM GMT — clocks spring forward to 2 AM in March and fall back to 1 AM in October.

What time is it in London when it is 9 AM in New York?

When New York is on EST (winter): London is 5 hours ahead, so 9 AM New York = 2 PM London. When New York is on EDT (summer) and London is on BST: London is still 5 hours ahead, so 9 AM EDT = 2 PM BST.

How do I convert GMT to EST?

EST is UTC−5. GMT is UTC+0. To convert GMT to EST, subtract 5 hours. 15:00 GMT = 10:00 EST. During EDT (summer), EST becomes EDT (UTC−4), so subtract 4 hours instead: 15:00 GMT = 11:00 EDT. Use our live converter above to handle DST automatically.

What is the time difference between the UK and Australia?

It depends which Australian state and which UK season. Sydney (AEST, UTC+10) is 10 hours ahead of London in UK winter, and 9 hours ahead in UK summer (BST). Sydney uses AEDT (UTC+11) in Australian summer (October–April), which aligns partly with UK winter — creating an 11-hour gap at maximum. Perth (AWST, UTC+8) is always 8 or 7 hours ahead depending on UK season. Use the multi-zone converter above to check all at once.