Compare GMT vs BST
See the current time difference between GMT and BST, check daylight saving effects, and find the best hours to schedule meetings.
How to Find the Time Difference Between GMT and BST
Open the GMT vs BST converter: Visit https://www.xconvert.com/time-converter/gmt-vs-bst to load a comparison grid with GMT and BST already shown as separate rows on a 24-hour timeline. This page is useful when you are scheduling a London meeting during British Summer Time, checking a broadcast slot, or confirming whether a GMT-based timestamp from a server log needs to be shifted for UK local summer time.
Add other cities if your schedule involves more than the UK: Click + Add City and search for places such as London, Dublin, or New York if you are coordinating media, finance, or remote engineering work that references GMT while teams actually operate on local summer time. For example, London businesses in banking, legal services, and advertising often work on BST in summer, while international partners may still label systems, contracts, or cloud infrastructure in GMT or UTC.
Drag across the grid to compare a real meeting window: Click Select, then drag on the GMT row from 09:00 to 11:00 to highlight that range in purple; the BST row will show the same moment as 10:00 to 12:00, because BST is 1 hour ahead of GMT. This is especially useful for avoiding off-by-one-hour mistakes when a UK office says “10 AM local time” in July but a legacy system or international colleague is still reading times in GMT.
Export the selected time range for your team: After selecting the range, use the export options for ICS download, Google Calendar, Gmail, Copy to clipboard, or Share link so everyone receives the converted time in their own calendar workflow. This is practical for sending a summer board meeting, a BBC-style broadcast schedule, or a cross-border support handoff where one side references GMT and the other uses BST on the day of the event.
GMT vs BST Offset Explained
BST is exactly 1 hour ahead of GMT. That means 12:00 GMT = 13:00 BST, 09:00 GMT = 10:00 BST, and 18:30 GMT = 19:30 BST. If you are comparing the two directly, BST never varies from GMT by anything other than +1 hour while BST is in effect.
GMT (Greenwich Mean Time) is UTC+0, while BST (British Summer Time) is UTC+1. GMT is the standard time used in the United Kingdom during the winter months, and BST is the daylight saving time used during the summer months. In practical terms, BST is not a separate year-round zone with its own independent base offset; it is the UK's seasonal summer clock setting, one hour ahead of GMT.
In the UK, BST begins at 1:00 AM GMT on the last Sunday in March, when clocks move forward to 2:00 AM BST. In 2025, that change happens on 30 March 2025. BST ends at 2:00 AM BST on the last Sunday in October, when clocks move back to 1:00 AM GMT; in 2025, that happens on 26 October 2025.
This seasonal shift matters for travel, operations, and software. A flight departure board at London Heathrow, a trading desk in the City of London, or a support team working with UK customers may use local UK civil time, which is BST in summer and GMT in winter. Meanwhile, cloud platforms, server logs, and international APIs often store timestamps in GMT/UTC-style references, which is why users frequently need to confirm whether a summer appointment should be read one hour later in the UK.
The distinction is especially important in industries with fixed global timing. Financial markets, newsrooms, aviation, and multinational customer support teams often coordinate around UTC or GMT labels, but staff in London, Manchester, Birmingham, and Edinburgh follow BST during summer. If a team sees 14:00 GMT on a summer operations sheet, the correct UK local working time is 15:00 BST, which can affect trading cutoffs, webinar start times, and airport transfer planning.
A simple rule helps: when the UK is on summer time, add 1 hour to GMT to get BST. So if it is 8 AM GMT, it is 9 AM BST; if it is 11 PM GMT, it is 12 AM BST the next day. This next-day rollover is important when planning overnight maintenance windows, publishing embargoes, or customer support shifts that cross midnight.
Frequently Asked Questions
What is the time difference between GMT and BST right now?
The standard difference is 1 hour, with BST ahead of GMT. However, this only applies during the British Summer Time period, which runs from the last Sunday in March to the last Sunday in October in the UK. Outside that period, the UK returns to GMT, so there is no difference between UK local time and GMT in winter.
Is BST always 1 hour ahead of GMT?
Yes, BST is always GMT+1 whenever BST is in effect. BST is the daylight saving time used in the United Kingdom, so it does not switch to +2 or any other offset. The only seasonal change is whether the UK is currently observing GMT (UTC+0) in winter or BST (UTC+1) in summer.
When do the clocks change from GMT to BST?
The UK changes from GMT to BST on the last Sunday in March each year. At 1:00 AM GMT, the clocks move forward by one hour to 2:00 AM BST, which means the hour from 1:00 to 1:59 AM local winter time is skipped. In 2025, this transition occurs on 30 March 2025.
When do the clocks change from BST back to GMT?
The UK returns from BST to GMT on the last Sunday in October. At 2:00 AM BST, the clocks move back one hour to 1:00 AM GMT, so the hour between 1:00 AM and 2:00 AM occurs twice in different offsets. In 2025, the fallback date is 26 October 2025, which is important for overnight travel, payroll systems, and timestamped logs.
How do I convert GMT to BST?
To convert GMT to BST, add 1 hour during the period when BST is active. For example, 07:00 GMT = 08:00 BST and 16:30 GMT = 17:30 BST. If the date falls outside the UK daylight saving period, then UK local time is GMT, so no conversion is needed.
Why do people confuse GMT and BST?
People often use “GMT” as a casual label for all UK time year-round, even though the UK actually uses BST in summer and GMT in winter. The confusion is common in event invitations, email threads, software dashboards, and international meeting planning, especially when one person says “London time” and another writes “GMT” for a July or August meeting. This can create a one-hour error if nobody checks the date.
Is London on GMT or BST?
London is on GMT during winter and BST during summer. Specifically, London follows BST from the last Sunday in March until the last Sunday in October, then switches back to GMT for the colder months. If you are booking meetings, flights, or theater tickets in London, the exact date determines which label is correct.
Does GMT observe daylight saving time?
No, GMT itself does not observe daylight saving time because it is a fixed offset of UTC+0. What changes is that the United Kingdom switches from using GMT in winter to using BST (UTC+1) in summer. This distinction matters in technical systems, because a fixed GMT timestamp remains unchanged while local UK civil time may shift by one hour seasonally.