Time in London: GMT, BST, and US–London Time Differences Explained

London holds a unique place in global timekeeping: it is the origin of all time zones. The Prime Meridian — 0° longitude — passes through the Royal Observatory in Greenwich, a district of southeast London. Every UTC offset in the world is calculated as hours ahead of or behind London's reference meridian.

Despite being the anchor for universal time, London itself shifts between two offsets throughout the year:

Key 2025–2026 DST dates for London:

• Spring forward (2025): Sunday, 30 March 2025 at 1:00 AM → clocks jump to 2:00 AM BST
• Fall back (2025): Sunday, 26 October 2025 at 2:00 AM → clocks fall to 1:00 AM GMT
• Spring forward (2026): Sunday, 29 March 2026 at 1:00 AM → clocks jump to 2:00 AM BST
• Fall back (2026): Sunday, 25 October 2026 at 2:00 AM → clocks fall to 1:00 AM GMT

Note that London's DST switchover happens on the last Sunday of March/October, while the United States switches on the second Sunday of March and first Sunday of November. This creates brief transition windows each year when the US–London offset is temporarily different from the standard:

During these transition windows, London is only 4 hours ahead of New York (instead of the usual 5), or 6 hours ahead. For a live display of the current London time, visit the World Clock. For UK-wide time information, see time in England.

London's position at UTC+0/+1 makes it a natural bridge between the Americas and Europe/Asia. For US professionals, the London offset is the most commonly needed international time calculation. Here is a comprehensive breakdown of London time versus all major US time zones.

London vs. US zones — Summer (US Daylight Time, London BST):

*Phoenix stays on MST (UTC−7) year-round, no DST.

London vs. US zones — Winter (US Standard Time, London GMT):

The London–NYC gap of 5 hours is one of the most stable international offsets, holding true for the vast majority of the year. The London–LA gap of 8 hours is the defining challenge for trans-Atlantic West Coast businesses — when Los Angeles starts its workday at 9 AM, London is already at 5 PM, meaning the London office is at end-of-day.

For detailed New York time comparisons including NYSE trading hours, see our NYC page. For Paris time and Berlin time comparisons from a US perspective, see those dedicated pages.

This is the complete 24-hour comparison between London and New York — the two most important financial cities in the English-speaking world. Use this table to instantly translate any London time to New York time and vice versa.

London (GMT, UTC+0) vs. New York (EST, UTC−5) — Winter schedule:

London (BST, UTC+1) vs. New York (EDT, UTC−4) — Summer schedule:

The London–NYC overlap window is the most active period in global financial markets. The 2-hour window when both the LSE and NYSE are simultaneously open (approximately 9:30 AM–11:30 AM ET / 2:30–4:30 PM London) sees the highest global trading volumes of any time period. Currency pairs like GBP/USD, EUR/USD, and USD/JPY are most liquid during this overlap.

The London Stock Exchange (LSE) is one of the world's oldest and largest stock exchanges, with a history dating back to 1698. For US investors and traders, understanding LSE hours in Eastern Time is essential for trading UK equities, UK-listed ETFs, and instruments that track London prices.

LSE Official Trading Schedule:

FTSE 100 Index: The Financial Times Stock Exchange 100 Index tracks the 100 largest companies by market capitalization listed on the LSE. Major components include Shell, AstraZeneca, HSBC, Unilever, BP, GSK, and Rio Tinto. The FTSE 100 is the primary barometer of UK economic health and is closely watched by US investors as a leading indicator before the NYSE opens.

The London–New York Trading Overlap (the most important window in forex):

When the NYSE opens at 9:30 AM ET, London has been trading for over 6 hours (since 8:00 AM GMT/3:00 AM ET). The simultaneous operation of both markets from 9:30 AM–11:30 AM ET accounts for approximately 40–50% of daily global forex trading volume. The EUR/USD, GBP/USD, and GBP/JPY pairs are all at peak liquidity during this window.

For US options traders: US-listed iShares UK ETFs (like EWU) trade during regular NYSE hours, but their underlying prices are determined during London trading hours. By the time the NYSE opens, the LSE has been setting prices for 6+ hours.

For tracking both markets in real time, the World Clock displays both London and New York times simultaneously. See also our New York time guide for NYSE hours from a London perspective.

Scheduling calls between the US and London requires careful coordination due to the 5–8 hour gap depending on which US time zone you're calling from. Here are the optimal windows and everything you need to know for visits to London.

Best times to call London from US cities (standard business hours 9 AM–5 PM for both parties):

For West Coast callers, the ideal window is challenging — 5:00–9:00 AM Pacific is before most people's workday starts. Many LA–London professionals use asynchronous tools (email, Slack) for most communication and reserve live calls for the 8:00–9:00 AM PT window, which is just barely within London's working hours (4:00–5:00 PM BST).

Alternatively — calling during London's morning from the US: London's morning (9:00–11:00 AM GMT/BST) corresponds to:

• 4:00–6:00 AM New York (ET) — too early for most
• 1:00–3:00 AM Los Angeles (PT) — impossible

The structural asymmetry means US East Coast callers have a workable window; US West Coast callers almost never have a natural overlap.

Heathrow Airport (LHR) guide for US travelers:

Jet lag traveling from US to UK: The eastward direction is harder for most people. Traveling from New York (+5 hours) produces moderate adjustment; from LA (+8 hours) is significant. Arriving in the morning and staying awake until London bedtime (10:00–11:00 PM GMT) is the standard advice.

London Underground (The Tube) hours:

• Monday–Saturday: First trains from ~5:00–5:30 AM GMT/BST, last trains ~12:30 AM GMT/BST
• Sunday: First trains from ~6:30–7:30 AM GMT/BST, last trains ~11:30 PM GMT/BST
• Night Tube (Fridays and Saturdays): Central, Jubilee, Northern, Piccadilly, and Victoria lines run 24 hours

West End theatre times: Evening performances typically begin at 7:30 PM GMT/BST. Matinees are usually 2:30–3:00 PM GMT/BST on Wednesdays and Saturdays. For US visitors, this is 2:30 PM ET / 11:30 AM PT for evening shows (in winter) — easy to remember as early afternoon New York time.