Learn the UK to USA time difference by US time zone, daylight saving changes, and the best hours for international calls.
The UK and United States span several time zones, so the time difference depends on the American city or state you are contacting. London does not have the same time difference with New York, Chicago, Denver, and Los Angeles. The gap can also change during parts of the year because the UK and most of the USA observe daylight saving time on different dates.
Knowing the correct time difference helps when scheduling international calls, remote work meetings, interviews, online classes, appointments, and family conversations. A time that works well in London may be very early in California or late in the evening in another location.
The easiest way to convert UK time to USA time is to identify the American time zone first. From there, you can subtract the appropriate number of hours and check whether either country is experiencing a daylight saving transition.
UK to USA Time Difference by Time Zone
The United States has several major time zones across the continental country. For international communication, the most commonly used are Eastern, Central, Mountain, and Pacific Time.
The UK uses Greenwich Mean Time (GMT) during its winter clock period and British Summer Time (BST) during its summer clock period.
The four main USA time zones are:
- Eastern Time
- Central Time
- Mountain Time
- Pacific Time
Under normal seasonal conditions, the approximate differences are:
| USA time zone | Difference behind UK |
|---|---|
| Eastern Time | 5 hours |
| Central Time | 6 hours |
| Mountain Time | 7 hours |
| Pacific Time | 8 hours |
These differences are not identical throughout the entire year because the UK and USA change their clocks on different dates.
UK to New York Time Difference
New York uses Eastern Time.
Under the usual winter and summer arrangements, New York is five hours behind London for much of the year.
For example, when London is 3:00 PM, New York is normally 10:00 AM.
A basic conversion looks like this:
| UK time | New York time |
|---|---|
| 8:00 AM | 3:00 AM |
| 9:00 AM | 4:00 AM |
| 10:00 AM | 5:00 AM |
| 11:00 AM | 6:00 AM |
| 12:00 PM | 7:00 AM |
| 1:00 PM | 8:00 AM |
| 2:00 PM | 9:00 AM |
| 3:00 PM | 10:00 AM |
| 4:00 PM | 11:00 AM |
| 5:00 PM | 12:00 PM |
| 6:00 PM | 1:00 PM |
| 7:00 PM | 2:00 PM |
| 8:00 PM | 3:00 PM |
Why the difference can temporarily change
The United Kingdom and United States do not change their clocks on exactly the same dates.
The USA generally begins daylight saving time earlier in spring than the UK and ends it later in autumn. During those short transition periods, the UK to New York difference can temporarily be four hours instead of five.
For important appointments, check the actual calendar date.
UK to Chicago Time Difference
Chicago uses Central Time.
Chicago is normally six hours behind London.
For example:
- 12:00 PM in London = 6:00 AM in Chicago
- 2:00 PM in London = 8:00 AM in Chicago
- 4:00 PM in London = 10:00 AM in Chicago
- 6:00 PM in London = 12:00 PM in Chicago
Chicago's Central Time also applies to many locations across the central United States.
A London-based person arranging a morning meeting with Chicago should therefore remember that the Chicago participant may be starting work several hours earlier.
UK to Denver Time Difference
Denver uses Mountain Time.
Denver is normally seven hours behind London.
For example:
| London | Denver |
|---|---|
| 9:00 AM | 2:00 AM |
| 10:00 AM | 3:00 AM |
| 11:00 AM | 4:00 AM |
| 12:00 PM | 5:00 AM |
| 1:00 PM | 6:00 AM |
| 2:00 PM | 7:00 AM |
| 3:00 PM | 8:00 AM |
| 4:00 PM | 9:00 AM |
| 5:00 PM | 10:00 AM |
| 6:00 PM | 11:00 AM |
| 7:00 PM | 12:00 PM |
This makes afternoon UK meetings more practical for people in Denver than early-morning London appointments.
UK to Los Angeles Time Difference
Los Angeles uses Pacific Time.
Los Angeles is normally eight hours behind London.
For example:
- 8:00 AM London = 12:00 AM Los Angeles
- 10:00 AM London = 2:00 AM Los Angeles
- 12:00 PM London = 4:00 AM Los Angeles
- 2:00 PM London = 6:00 AM Los Angeles
- 4:00 PM London = 8:00 AM Los Angeles
- 6:00 PM London = 10:00 AM Los Angeles
- 8:00 PM London = 12:00 PM Los Angeles
This makes late afternoon and evening UK calls particularly useful for people in California.
For example, a 6:00 PM London call normally occurs at 10:00 AM in Los Angeles.
UK to USA Time Difference Chart
A quick chart makes international scheduling easier.
| UK time | New York | Chicago | Denver | Los Angeles |
|---|---|---|---|---|
| 8 AM | 3 AM | 2 AM | 1 AM | 12 AM |
| 9 AM | 4 AM | 3 AM | 2 AM | 1 AM |
| 10 AM | 5 AM | 4 AM | 3 AM | 2 AM |
| 11 AM | 6 AM | 5 AM | 4 AM | 3 AM |
| 12 PM | 7 AM | 6 AM | 5 AM | 4 AM |
| 1 PM | 8 AM | 7 AM | 6 AM | 5 AM |
| 2 PM | 9 AM | 8 AM | 7 AM | 6 AM |
| 3 PM | 10 AM | 9 AM | 8 AM | 7 AM |
| 4 PM | 11 AM | 10 AM | 9 AM | 8 AM |
| 5 PM | 12 PM | 11 AM | 10 AM | 9 AM |
| 6 PM | 1 PM | 12 PM | 11 AM | 10 AM |
| 7 PM | 2 PM | 1 PM | 12 PM | 11 AM |
| 8 PM | 3 PM | 2 PM | 1 PM | 12 PM |
| 9 PM | 4 PM | 3 PM | 2 PM | 1 PM |
This table represents the usual five-, six-, seven-, and eight-hour differences. Short periods around seasonal clock changes can differ.
Best Time to Call the USA From the UK
The best time depends on the American time zone and whether the call is personal or professional.
For business communication, a useful London calling window is often 3:00 PM to 7:00 PM UK time.
During that period, the approximate US times are:
- New York: 10:00 AM to 2:00 PM
- Chicago: 9:00 AM to 1:00 PM
- Denver: 8:00 AM to 12:00 PM
- Los Angeles: 7:00 AM to 11:00 AM
This window can cover ordinary working hours across several US regions.
Best time for New York calls
A London caller can consider approximately 2:00 PM to 6:00 PM UK time for many business conversations with New York.
This corresponds roughly to 9:00 AM to 1:00 PM in New York under the usual five-hour difference.
Best time for California calls
California requires more attention because it is eight hours behind London under normal conditions.
A call around 5:00 PM to 8:00 PM UK time corresponds roughly to 9:00 AM to 12:00 PM in Los Angeles.
This can provide a comfortable overlap between London afternoon and California morning.
UK and USA Daylight Saving Time
Daylight saving time is one of the main reasons people sometimes see an unexpected one-hour difference.
The United Kingdom uses GMT during its standard winter period and BST during its summer clock period.
Most of the USA uses standard time during part of the year and daylight time during another part.
However, the dates do not match exactly.
Why this matters
Suppose a London company has a recurring video meeting with a New York team.
For much of the year, the meeting may show a five-hour difference. During a short period when one country has changed its clocks and the other has not, the difference can become four hours.
A calendar application that knows the locations can normally account for this automatically.
For manual scheduling, always use the exact date.
UK to USA Time for Business Meetings
International businesses often work across several American time zones. A meeting that is convenient for New York may be difficult for California.
For example, a 2:00 PM London meeting is approximately:
- 9:00 AM in New York
- 8:00 AM in Chicago
- 7:00 AM in Denver
- 6:00 AM in Los Angeles
If participants are spread across the United States, moving the meeting later in London can provide a more balanced overlap.
A 6:00 PM London meeting is approximately:
- 1:00 PM in New York
- 12:00 PM in Chicago
- 11:00 AM in Denver
- 10:00 AM in Los Angeles
The appropriate time depends on the participants' working hours and personal schedules.
UK to USA Time for Travel and Flights
Time-zone differences also matter when traveling between Britain and America.
Flight itineraries normally display local departure and arrival times. A flight leaving London in the morning can arrive in the United States at an apparently earlier clock time because the aircraft crosses several time zones.
Travelers should therefore distinguish between:
- Departure time in the UK
- Flight duration
- Arrival time in the USA
- Local time at the destination
- Seasonal clock changes
A person traveling to New York, Chicago, Denver, or Los Angeles should check the local time at the destination rather than attempting to convert every flight time manually.
Practical Examples and Tips
If you live in London and need to call someone in the USA, start by identifying the city.
A 4:00 PM London call is normally 11:00 AM in New York, 10:00 AM in Chicago, 9:00 AM in Denver, and 8:00 AM in Los Angeles.
For a California business contact, a 6:00 PM London call is normally 10:00 AM in Los Angeles. For New York, the same call is normally 1:00 PM.
Before sending an invitation, include the city and date. Avoid writing only "4 PM UK time" when several people are involved. A calendar invitation with London and the relevant US location can reduce mistakes, especially around daylight saving changes.
For recurring meetings, review the schedule when either country changes its clocks. A one-hour difference can temporarily appear or disappear even though nobody changed the meeting themselves.
FAQs About UK to USA Time Difference
1. How many hours is the UK ahead of the USA?
The UK is normally five to eight hours ahead of the major US time zones in the continental United States. New York is generally five hours behind London, Chicago six hours behind, Denver seven hours behind, and Los Angeles eight hours behind.
The exact difference can temporarily change because the UK and USA do not change their clocks on exactly the same dates. This is especially noticeable during the weeks between the American and British daylight saving transitions.
For an important call, use the actual date and destination city rather than relying only on the standard difference. This is particularly important for business meetings, interviews, online appointments, and recurring calendar events.
2. Is New York five hours behind the UK?
New York is normally five hours behind the United Kingdom when both countries are in their corresponding standard or daylight periods. For example, 3:00 PM in London is generally 10:00 AM in New York.
There are short periods during the year when the difference can be four hours because the United States and United Kingdom change their clocks on different dates.
This means a fixed "five hours" rule is useful for much of the year but should not replace a date-specific check for important appointments. Calendar applications using London and New York locations can account for seasonal clock changes.
3. How many hours behind is California from the UK?
California, including Los Angeles, is normally eight hours behind the United Kingdom. Therefore, 6:00 PM in London is generally 10:00 AM in Los Angeles.
California uses Pacific Time, which creates a larger difference than the Eastern Time used in New York. The difference can temporarily change around the seasonal clock transitions because the UK and USA do not adjust their clocks on exactly the same dates.
For business calls, late afternoon or early evening in London can therefore be suitable for California mornings. Always check the specific date when arranging an important meeting.
4. What time is 9 AM in the UK in New York?
Under the usual five-hour difference, 9:00 AM in the UK is 4:00 AM in New York. This is generally too early for an ordinary business meeting.
For a more practical overlap, a London meeting around 2:00 PM corresponds to approximately 9:00 AM in New York. A 4:00 PM London meeting corresponds to about 11:00 AM in New York.
The exact difference can temporarily change around daylight saving transitions. Therefore, people arranging interviews, appointments, or business calls should check the date and use a time-zone-aware calendar.
5. What time is 6 PM in the UK in America?
There is no single American answer because the USA has multiple time zones. Under the usual differences, 6:00 PM in London is approximately 1:00 PM in New York, 12:00 PM in Chicago, 11:00 AM in Denver, and 10:00 AM in Los Angeles.
These times make a 6:00 PM London call potentially useful for business conversations across several US regions.
The exact conversion can change temporarily around daylight saving transitions. The destination city and appointment date should therefore be included when scheduling an international call.
6. Does the UK have daylight saving time?
Yes. The UK uses British Summer Time during its seasonal daylight saving period and Greenwich Mean Time during the standard winter period.
The seasonal clock change affects the time difference between Britain and the United States. The USA also has daylight saving time in most states, but its transition dates do not exactly match those used in Britain.
As a result, the UK to USA time difference can temporarily differ from the usual five to eight hours. This matters most for recurring meetings scheduled around March and autumn clock changes.
7. What is the best time for a UK business to call America?
The suitable time depends on where the American contact is located. A London call during the afternoon can overlap with morning and early afternoon working hours in the United States.
For example, a 4:00 PM London meeting is normally about 11:00 AM in New York, 10:00 AM in Chicago, 9:00 AM in Denver, and 8:00 AM in Los Angeles.
If the American team includes people from several time zones, a later London meeting can provide more balanced working hours. The participants' schedules should be considered before choosing the final time.
8. Why does the UK to USA time difference sometimes change by one hour?
The difference changes because Britain and the United States do not switch between standard time and daylight saving time on exactly the same dates.
For much of the year, the familiar differences apply: five hours to Eastern Time, six to Central Time, seven to Mountain Time, and eight to Pacific Time.
During the transition periods, one country may have changed its clocks while the other has not. The difference can therefore temporarily be one hour smaller or larger than usual.
For important meetings, checking the exact date in a time-zone-aware calendar is safer than using a fixed conversion.
Conclusion
The UK to USA time difference depends mainly on the American time zone. London is normally five hours ahead of New York, six hours ahead of Chicago, seven hours ahead of Denver, and eight hours ahead of Los Angeles. Seasonal clock changes can temporarily alter these differences.
For current clock-change information and official time rules, the UK government clock change information provides dates for British Summer Time and the return to Greenwich Mean Time. Checking the date and destination city before an international call can help prevent scheduling errors.
For work, travel, interviews, family calls, and online meetings, writing both local times in the invitation is a simple way to avoid confusion. A time-zone-aware calendar is especially useful when meetings repeat throughout the year.
