Time difference between the UK and USA

One gap for every US time zone

There is no single time difference between the UK and the USA, because the country spans four main zones and a handful of others. From London you add nothing for Britain itself and subtract five hours for Eastern, six for Central, seven for Mountain and eight for Pacific. A simple way to remember it is that the number of hours behind equals the number of time zones you cross on the way west.

The gaps are stable for most of the year because the UK and most of the US both move their clocks by one hour in the same direction. When Britain is on British Summer Time (UTC+1) the US is on daylight time too, so New York is still five hours behind London from the end of March to the end of October. Winter works the same way with GMT against standard time.

The weeks when the gap is one hour shorter

The catch is that the two sides do not move on the same date. The US springs forward on the second Sunday of March, while the UK waits until the last Sunday. In the autumn the UK falls back on the last Sunday of October and the US follows a week later, on the first Sunday of November. In between, one side is on summer time and the other is not, and the gap drops from five hours to four for Eastern (six to five for Central, seven to six for Mountain, eight to seven for Pacific).

This year the spring window ran from 8 to 29 March, three full weeks, and the autumn one from 25 October to 1 November. The next ones fall on 14 to 28 March 2027 and 31 October to 7 November 2027. A weekly call fixed at 2:00 PM London that is 9:00 AM in New York for most of the year becomes 10:00 AM New York time for those two weeks in March 2027, and anyone who set the time in their head rather than in a calendar will turn up an hour off.

Financial markets across the Atlantic

The London Stock Exchange trades from 8:00 AM to 4:30 PM UK time, and the New York Stock Exchange from 9:30 AM to 4:00 PM Eastern. With a five-hour gap New York opens at 2:30 PM London time, so the two markets are open together for two hours, from 2:30 PM to 4:30 PM in London. In the short windows when the gap is four hours the overlap grows to three hours, because New York opens at 1:30 PM London time while London still closes at 4:30 PM.

For US-based traders watching London, the open is very early: 8:00 AM in London is 3:00 AM in New York and midnight in Los Angeles. Many West Coast desks therefore look at the European close rather than the open.

Football, rugby and the NFL in London

Sport is where most casual viewers meet the time difference. A Premier League match with a 12:30 PM Saturday kick-off is 7:30 AM on the East Coast and 4:30 AM in California, which is why American fans tend to watch those games with breakfast or on replay. A traditional 3:00 PM kick-off is 10:00 AM Eastern or 7:00 AM Pacific.

The NFL plays a few games a year in London, usually in the autumn, with an early kick-off for the UK audience. A 2:30 PM start in London works out at 9:30 AM Eastern and 6:30 AM Pacific. Both countries are still on summer time for most of those games, so the five-hour and eight-hour gaps apply.

Flights, jet lag and the first day abroad

Flying from the UK to the US means gaining time on the way out and losing it coming home. Leaving Heathrow at 9:00 AM for New York, a flight of roughly eight hours, you land at about noon local time on the same day, which is why the first day on arrival feels very long. The return leg is the opposite: an evening departure from New York arrives in London the following morning, with five hours missing from the night.

Travellers to California face an eight-hour shift, enough to be awake at 4:00 AM for the first few days. A useful habit is to set your phone to the destination time zone as you board and to schedule any calls with the home office at the overlap, not at your body clock.

Alaska, Hawaii and Arizona

The four columns of the table are not the whole US. Alaska is nine hours behind the UK for most of the year, shrinking to eight hours only during the weeks when the UK is on GMT and Alaska has already moved to daylight time. Hawaii does not change its clocks, so it is ten hours behind in winter and eleven during British Summer Time. Most of Arizona also stays on UTC−7: seven hours behind the UK in winter and eight in summer.

UK and US clock changes, 2026 to 2027

The table below lists every clock change that affects this pair, with the gap that results for each US time zone. All US zones change on the same date, so one row covers them all, and the UK change is separate.

Every clock change that affects this pair

The gap, window by window

Business-hours overlap

Times in the table are in United Kingdom time. The first column of results assumes a normal 9 AM to 5 PM day at both ends, using today’s offsets; the second uses July 2027; the third stretches both days to 7 AM to 10 PM, which is the realistic window when one team is willing to start early or finish late.

Finance and media teams usually use the three hours from 2:00 PM to 5:00 PM London time, which is 9:00 AM to 12:00 PM in New York, as the standing window for a transatlantic call. West Coast teams typically hold their side of the call early (7:00 AM to 9:00 AM Pacific, 3:00 PM to 5:00 PM London) and many UK colleagues stay on until 5:00 or 6:00 PM to make it work.