The short answer: the UK (GMT in winter, BST — UTC+1 — in summer) is 5 hours ahead of US Eastern Time and 8 hours ahead of US Pacific for most of the year. The easiest time to call the UK from the US is your morning: around 8:00–11:00 AM ET lands at roughly 1:00–4:00 PM in London. From the West Coast, aim for 8:00–10:00 AM PT (about 4:00–6:00 PM in London).
The UK and the United States share a workday more comfortably than most transatlantic pairs. The UK is ahead, but only by a handful of hours, so your morning to their afternoon is a wide, reliable overlap rather than a narrow squeeze.
How far ahead is the UK?
The UK runs on GMT in winter and shifts to British Summer Time (UTC+1) in summer. The US changes its clocks too, so for most of the year the gap holds steady, with a brief wobble during the few weeks each spring and autumn when the two countries are out of sync.
| Your US zone | UK ahead of you (most of year) | UK ahead of you (clocks out of sync) |
|---|---|---|
| Eastern (ET) | 5 hours | 4 hours |
| Pacific (PT) | 8 hours | 7 hours |
The best windows to call
Because the UK is ahead, your morning is their afternoon. Aim for the middle of the UK working day, which is still early enough on your side to be a clean, sociable hour.
| Calling from | Call at (your time) | In London |
|---|---|---|
| US East Coast (ET) | 8:00 AM | 1:00 PM |
| US East Coast (ET) | 11:00 AM | 4:00 PM |
| US Pacific (PT) | 8:00 AM | 4:00 PM |
| US Pacific (PT) | 10:00 AM | 6:00 PM |
For the full picture of how the two countries line up across the day, see our guide to the USA–UK time zone difference, or the city-level breakdown in London vs New York time.
For a business call vs a personal call
For a work call, the cleanest overlap is your morning against the UK afternoon: from the East Coast, 8–11 AM ET catches London squarely in the back half of its workday. From the West Coast, 8–10 AM PT reaches the UK as it heads into early evening, ideal for a wrap-up before colleagues sign off.
For a personal call to family, the same window works well: a mid-morning call your time is a relaxed afternoon or early evening in the UK, before dinner and well clear of bedtime.
Both the UK and the US observe daylight saving, but they switch on slightly different dates. For about three weeks each spring and autumn the usual offset is one hour smaller, so a recurring call can land an hour off until both countries have changed their clocks. See our guide to the USA–UK time zone difference.
Stop checking this every time
If you call or meet the UK regularly, doing this arithmetic by hand gets old fast, and it's exactly where the daylight-saving mistakes creep in. Atlas keeps London and your own city side by side in your Mac menu bar, shades the hours when both sides are awake, and writes any meeting to your calendar in both local times. One glance tells you whether now is a good time to call.
Frequently asked
How many hours ahead is the UK of the USA?
What is the best time to call the UK from the US?
Does the UK observe daylight saving time?
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