Time difference between the United States and the United Kingdom

Q: What is the time difference between the United States and the United Kingdom?

There is no single figure. the United States spans 6 of the offsets in this data, so the difference runs from 5 hours (New York to London) to 11 hours (Honolulu to London). Any converter giving one number for this pair has quietly picked a city.

5 hours to 11 hours, depending on the city

Why there is no single answer

The United States spans 6 different offsets in this data — New York at UTC−5, Chicago at UTC−6, Denver at UTC−7, Los Angeles at UTC−8, Anchorage at UTC−9, Honolulu at UTC−10. One number cannot cover 6 offsets, so any single figure for "the United States to the United Kingdom" is a choice of city — declared or not. That is why two sources can both be right and still disagree, and why the useful answer is the table rather than the number.

Every combination

From	To	Usual difference	Changes in the year
New York	London	5 hours ahead	yes — also 4 hours
Chicago	London	6 hours ahead	yes — also 5 hours
Denver	London	7 hours ahead	yes — also 6 hours
Los Angeles	London	8 hours ahead	yes — also 7 hours
Anchorage	London	9 hours ahead	yes — also 8 hours
Honolulu	London	11 hours ahead	yes — also 10 hours

When the gap moves

6 of these 6 combinations change by an hour at some point in the year. New York, Chicago, Denver, Los Angeles and Anchorage go forward on the second Sunday in March and back on the first Sunday in November; Honolulu does not change its clocks; London goes forward on the last Sunday in March and back on the last Sunday in October. Where the two sides change on different weekends, there is a stretch of days when the difference is what neither party expects.

Frequently asked questions

What is the time difference between the United States and the United Kingdom?

There is no single figure. the United States spans 6 of the offsets in this data, so the difference runs from 5 hours (New York to London) to 11 hours (Honolulu to London). Any converter giving one number for this pair has quietly picked a city.

How many hours ahead is the United Kingdom of the United States?

It depends which part of the United States you mean. The table on this page gives every combination; the extremes are 5 hours and 11 hours.

Does the difference between the United States and the United Kingdom change during the year?

Yes. 6 of the 6 city combinations here shift by an hour at some point, because the two sides change their clocks on different weekends or one of them does not change at all.

About these places

New York. New York is UTC−5 in winter and UTC−4 from March to November, and it changes clocks on different weekends from Europe — a fortnight in March and a week in autumn when the transatlantic gap is an hour off what everyone expects.

Chicago. Chicago is UTC−6 in winter, the US Central zone, and the one people most often mean by an unqualified "CST" — a reading that collides with China Standard Time fourteen hours the other way.

Denver. Denver is UTC−7 in winter, the US Mountain zone, and the smallest of the four continental US zones by population. Arizona, in the same zone, does not change its clocks, so for half the year Denver and Phoenix are an hour apart.

Los Angeles. Los Angeles is UTC−8 in winter and UTC−7 from March to November. California voted in 2018 to move to permanent daylight saving and has not been able to: the change needs an act of Congress, which has not come.

Anchorage. Alaska is UTC−9 in winter, one hour behind the US Pacific coast, and covers a longitude range that would justify four zones. The state consolidated into one in 1983 so that Anchorage business hours would overlap with the rest of the country.

Honolulu. Hawaii is UTC−10 and does not change its clocks, so it drifts an hour further from the mainland every March. It is the furthest behind of any populated US zone, and the overlap with a European working day is essentially nil.

London. London is the reference the rest of the system is measured from: Greenwich sits inside the city, and UTC±0 is its winter time. It does not stay there — Britain moves to UTC+1 for seven months of the year, which is why "London is GMT" is wrong more often than it is right.

The same pair from the other end

This page reads the difference as the United Kingdom against the United States. The United Kingdom to the United States states the same gap the other way round, which is the one to send someone if they are the one doing the travelling.

Other country pairs

Every the United States pair · All country pairs · City pairs