Best Time to Call the UK from the USA

Understanding the Time Gap Between the USA and the UK

The US-UK time gap is one of the most manageable among major transatlantic business relationships. Unlike US-India or US-Australia scheduling, the gap is small enough that a meaningful overlap window exists during normal business hours on both sides.

The UK operates on Greenwich Mean Time (GMT, UTC+0) during winter and British Summer Time (BST, UTC+1) during summer. The continental United States spans four time zones from UTC-5 (Eastern) to UTC-8 (Pacific), with DST shifting each zone forward by one hour from mid-March to early November.

The resulting gap ranges from just 5 hours (EDT to BST) to 8 hours (PST to GMT) — narrow enough that with modest flexibility, both sides can find a comfortable meeting time.

Complete Time Zone Comparison: USA vs. UK

*These figures apply when both the US and UK are on DST simultaneously. During the brief periods when only one country is on DST (see below), the gap shifts by one hour.

Best Call Windows by US Region

The US-UK relationship benefits from a relatively small time gap, making it possible to schedule calls during comfortable hours for both parties. The key principle: US morning to early afternoon aligns with UK afternoon to early evening.

Eastern Time (ET) Callers

Eastern Time has the easiest overlap with the UK of any US zone.

During standard time (US & UK both on standard time, roughly November–March):

• 8:00 AM–12:00 PM EST = 1:00 PM–5:00 PM GMT (excellent window)
• 9:00 AM–11:00 AM EST = 2:00 PM–4:00 PM GMT (sweet spot — peak energy on both sides)

During DST (both on DST, roughly late March–October):

• 8:00 AM–12:00 PM EDT = 1:00 PM–5:00 PM BST (same clock times, same great overlap)
• 9:00 AM–11:00 AM EDT = 2:00 PM–4:00 PM BST (sweet spot)

The gap shrinks to just 4 hours during summer, giving East Coast teams enormous flexibility. A 1:00 PM EDT call lands at 6:00 PM BST — late but still within the workday for the UK.

Central Time (CT) Callers

Standard time:

• 8:00 AM–11:00 AM CST = 2:00 PM–5:00 PM GMT (good window)
• 9:00 AM–10:30 AM CST = 3:00 PM–4:30 PM GMT (sweet spot)

DST:

• 8:00 AM–11:00 AM CDT = 2:00 PM–5:00 PM BST (same clock time overlap)
• 8:30 AM–10:30 AM CDT = 2:30 PM–4:30 PM BST (optimal)

Mountain Time (MT) Callers

Standard time:

• 7:00 AM–10:00 AM MST = 2:00 PM–5:00 PM GMT
• 8:00 AM–9:30 AM MST = 3:00 PM–4:30 PM GMT (optimal)

DST:

• 7:00 AM–10:00 AM MDT = 2:00 PM–5:00 PM BST
• 8:00 AM–9:30 AM MDT = 3:00 PM–4:30 PM BST

Mountain Time callers need to start slightly earlier than Eastern colleagues, but the window remains very workable.

Pacific Time (PT) Callers

Pacific Coast teams face the largest gap within the US-UK relationship, but it is still far more manageable than Pacific-to-India or Pacific-to-Australia.

Standard time:

• 6:00 AM–9:00 AM PST = 2:00 PM–5:00 PM GMT
• 7:00 AM–8:30 AM PST = 3:00 PM–4:30 PM GMT (optimal but early)

DST:

• 6:00 AM–9:00 AM PDT = 2:00 PM–5:00 PM BST
• 7:00 AM–8:30 AM PDT = 3:00 PM–4:30 PM BST

A 7:00 AM Pacific call is early but not unreasonable. Many West Coast companies with UK partnerships simply start the day with a UK sync and then move on to domestic work.

The Sweet Spot: US Morning = UK Afternoon

The single most important scheduling principle for US-UK calls is this: your morning is their afternoon. This is not just a time zone fact — it has real implications for meeting quality.

Why This Window Works So Well

• US participants are in their first few hours of the workday, when energy and focus are highest.
• UK participants are in their afternoon, still productive but approaching the end of their day. They are motivated to make decisions and wrap up — no one wants to leave an unresolved discussion hanging until tomorrow.
• Neither side is eating into personal time unless the call runs past 5:00 PM UK time or starts before 7:00 AM US time.

The Worst Window: US Late Afternoon

Avoid scheduling calls after 3:00 PM ET (8:00 PM GMT/BST). By this point, most UK offices have closed, and you are asking colleagues to join from home during their evening. Persistent late-afternoon US calls to the UK are a fast way to damage a working relationship.

How DST Affects the US-UK Gap

Here is where US-UK scheduling gets slightly tricky. Both countries observe DST, but they do not change their clocks on the same dates. This creates two brief periods each year where the gap is different from what you might expect.

The DST Transition Mismatch

The critical windows:

• Mid-March to late March: The US springs forward, but the UK has not yet moved to BST. The gap temporarily shrinks to 4 hours (ET to UK). A 9:00 AM EDT call lands at 1:00 PM GMT instead of the usual 2:00 PM.
• Late October to early November: The UK falls back to GMT, but the US is still on DST. Again, the gap temporarily becomes 4 hours. A 9:00 AM EDT call hits 1:00 PM GMT.

These transitions last roughly 2–3 weeks each and are the most common times for scheduling confusion. Calendar tools usually handle the conversion automatically, but human expectations about what time it is in the other country can lag behind the clock changes.

Key Dates to Remember

• US spring forward: Second Sunday in March
• UK spring forward: Last Sunday in March
• UK fall back: Last Sunday in October
• US fall back: First Sunday in November

The US changes clocks 2–3 weeks before the UK in spring, and the UK changes 1 week before the US in fall. During these gaps, verify the time difference explicitly before scheduling.

Industry-Specific Scheduling Advice

Finance and the London Hours Factor

London is one of the world's three major financial centers (alongside New York and Tokyo). The London Stock Exchange opens at 8:00 AM and closes at 4:30 PM GMT/BST. The New York Stock Exchange opens at 9:30 AM and closes at 4:00 PM ET.

The London-New York overlap is one of the most important windows in global finance:

The golden overlap for finance professionals is 9:30 AM–11:30 AM EST / 2:30 PM–4:30 PM GMT, when both markets are open simultaneously. This is when the highest trading volume occurs and when real-time coordination between London and New York desks matters most.

If your work involves UK financial regulation (FCA compliance, MiFID II reporting, or LIBOR transition matters), schedule calls during this market overlap window. UK financial regulators and legal teams are most available when the markets are active.

Technology and Software

US-UK tech collaboration is relatively straightforward. Common patterns include:

• Morning standup at 9:00 AM ET / 2:00 PM GMT: Both sides are well within their workday. This is the default for most US-UK tech teams.
• All-hands at 11:00 AM ET / 4:00 PM GMT: Works for larger meetings where the UK team stays slightly late.
• Asynchronous-first workflow: Given the manageable gap, many US-UK tech teams rely on Slack, Jira, and GitHub for day-to-day communication and reserve calls for sprint planning, demos, and architecture reviews.

Creative and Media

The creative industries (advertising, publishing, film, and media) often have more flexible schedules, but deadlines are no less rigid. Key considerations:

• London advertising agencies typically work 9:00 AM–6:00 PM GMT. A 10:00 AM ET / 3:00 PM GMT call works well for creative reviews.
• Publishing houses in London may have earlier schedules, with editors often in by 8:30 AM GMT. A 9:00 AM ET / 2:00 PM GMT call captures them at a productive point.
• Film and production schedules are notoriously irregular. For production coordination, the best approach is to agree on a daily check-in time at the start of each project rather than assuming a standard slot.

Common Mistakes to Avoid

1. Assuming the UK Is Always on GMT

The UK switches to British Summer Time (BST, UTC+1) from late March to late October. If you schedule a call at "9 AM your time, 2 PM GMT" during summer, you are actually calling at 2 PM BST — which is the same as 1 PM GMT. Your UK colleague will be an hour early or late depending on how the invitation was framed. Always specify whether you mean GMT or BST.

2. Scheduling After 5:00 PM UK Time Without Asking

While 5:00 PM is the nominal end of the UK workday, many British professionals work later. However, assuming they will be available past 5:00 PM is different from asking. A quick "Would 5:30 PM your time work?" goes a long way.

3. Ignoring the DST Transition Gap

As detailed above, the 2–3 week periods in March and October when only one country has changed clocks are prime times for missed meetings. Set a calendar reminder for these transitions.

4. Confusing UK Time with European Time

The UK is not on Central European Time (CET/CEST). London is one hour behind Berlin, Paris, and Amsterdam. If you are coordinating a call with both UK and continental European participants, the UK will always be one hour earlier. A 10:00 AM ET / 3:00 PM GMT call is 4:00 PM CET.

5. Not Accounting for UK Bank Holidays

The UK has eight permanent bank holidays per year, plus occasional one-off holidays (such as the King's Coronation in 2023). Key dates include Good Friday, Easter Monday, Early May Bank Holiday, Spring Bank Holiday, Summer Bank Holiday, Christmas, Boxing Day, and New Year's Day. Scotland has slightly different bank holidays than England and Wales. Always verify before scheduling critical calls.

Practical Scheduling Checklist

• Identify your US time zone and confirm your UK counterpart's location — the UK is unified on one time zone, but verify they are not traveling
• Check whether the UK is on GMT or BST — use UniversalTimeDate if unsure
• Aim for 9:00 AM–11:00 AM ET / 2:00 PM–4:00 PM UK time — this is the gold standard
• Avoid calls after 5:30 PM UK time unless explicitly agreed
• Check UK bank holidays — especially around Christmas, Easter, and the May/August bank holidays
• Send calendar invites with both time zones displayed — this prevents confusion during DST transitions
• Set reminders for DST change dates — mid-March and late October/early November
• Consider async alternatives — the US-UK gap is small enough that email and Slack often suffice for routine matters

FAQ

What is the time difference between the USA and the UK?

The time difference ranges from 4 hours (Eastern Daylight Time to British Summer Time) to 8 hours (Pacific Standard Time to GMT). For the most common pairing — Eastern Time to UK time — the gap is usually 5 hours, briefly shrinking to 4 hours during DST transition periods.

What is the best time for a video call with the UK from the US East Coast?

The best time is 9:00 AM–11:00 AM EST/EDT, which corresponds to 2:00 PM–4:00 PM GMT/BST. This captures both sides during their most productive hours and avoids encroaching on UK evening time.

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. The clocks spring forward one hour in March and fall back in October.

Why do the US and UK change clocks on different dates?

The US changes clocks on the second Sunday in March and the first Sunday in November, while the UK changes on the last Sundays in March and October. This creates a 2–3 week gap in spring and a 1-week gap in fall when the time difference is temporarily one hour less than usual.

Is 5:00 PM UK time too late for a business call?

It is at the edge. Most UK professionals will accept a call at 5:00 PM, but it should be the exception rather than the rule. Calls starting at 5:30 PM or later UK time should be reserved for urgent matters and always confirmed in advance.

What about calls with UK-based teams that work US hours?

Some UK-based teams — particularly in financial services and BPO operations — work shifted hours to align with the US. These teams may start at 1:00 PM–2:00 PM GMT and work until 10:00 PM–11:00 PM GMT. If your UK counterpart works US hours, schedule calls during US business hours as you normally would domestically.

How do I handle the DST transition confusion?

Three strategies: (1) always use time zone-aware calendar tools, (2) explicitly state both times in your meeting invitations ("9:00 AM ET / 2:00 PM GMT"), and (3) set a personal reminder for the week before each DST change to review upcoming UK meetings.

What is the worst time to call the UK from the USA?

Any time after 3:00 PM PT / 6:00 PM ET is the wrong time for a standard business call. This corresponds to after 11:00 PM in the UK. For Pacific Time callers specifically, avoid scheduling UK calls after 12:00 PM PST (8:00 PM GMT), as this pushes well into the UK evening.