GMT vs BST Time Difference

How to Find the Time Difference Between GMT and BST

GMT (Greenwich Mean Time, UTC+0) and BST (British Summer Time, UTC+1) are one hour apart, with British Summer Time 1 hour ahead of Greenwich Mean Time. This comparison is useful when you are scheduling meetings with teams in the United Kingdom, confirming summer business hours, or avoiding mistakes when a calendar invite shows GMT while local UK clocks are on British Summer Time.

Looking for Bangladesh Standard Time? See /time-converter/bst-bangladesh-time-zone.
Looking for Bougainville Standard Time? See /time-converter/bst-bougainville-time-zone.

1. Open the GMT vs BST page: Visit https://www.xconvert.com/time-converter/gmt-vs-bst to see Greenwich Mean Time and British Summer Time laid out on the visual comparison grid. This page is especially useful if you are planning a client call with a London-based team during the summer period, when UK business hours are shown as British Summer Time rather than Greenwich Mean Time.

2. Add comparison cities if your schedule involves more than the UK: Click + Add City and search for places that commonly work with the United Kingdom, such as London for UK office hours, Dublin for nearby cross-border coordination, or Accra for teams operating on Greenwich Mean Time year-round. This helps remote teams in finance, logistics, media, and customer support see whether a UK summer meeting shifts by one hour against locations that remain on GMT.

3. Drag across the grid to compare a working window: Click Select, then drag across the colored timeline to highlight a range in purple, such as 9:00 to 12:00 on the Greenwich Mean Time row, and compare it directly with 10:00 to 13:00 on the British Summer Time row. You can drag the center of the purple block to move the meeting window or use the left and right handles to resize it, which is useful when you need to test whether a morning operations call still fits UK office hours after the switch to British Summer Time.

4. Export the selected time range for your team: After selecting a range, use the export options for ICS download, Google Calendar, Gmail, Copy to clipboard, or Share link. This is practical when you need to send a confirmed meeting slot to a distributed team, attach it to a project handoff, or share a summer-hours schedule with colleagues so everyone sees the correct local time automatically.

GMT vs BST Offset Explained

BST (British Summer Time, UTC+1) is 1 hour ahead of GMT (Greenwich Mean Time, UTC+0). That means when it is 9:00 GMT, it is 10:00 BST; when it is 12:00 GMT, it is 13:00 BST; when it is 15:00 GMT, it is 16:00 BST; and when it is 18:00 GMT, it is 19:00 BST. For business scheduling, this matters because a workday labeled in Greenwich Mean Time will appear one hour later on a British Summer Time clock.

Greenwich Mean Time is a standard-time abbreviation, while British Summer Time is its daylight saving counterpart. In practical terms, the United Kingdom uses British Summer Time for the summer period, so meeting planners, airlines, broadcasters, and customer-facing teams often need to confirm whether a schedule is being published in GMT or in British Summer Time before sending invites or staffing rotas.

This distinction is especially important in sectors that rely on precise timing, including London financial services, UK media production, transport operations, and multinational support teams. If a trading desk, newsroom, or travel coordinator reads a schedule in GMT while local UK offices are working in British Summer Time, every appointment can appear one hour early unless the abbreviation is checked carefully.

Where GMT and British Summer Time Are Used

GMT (Greenwich Mean Time) is used across Burkina Faso, Gambia, Ghana, Guernsey, Guinea, Guinea-Bissau, Iceland, Ireland, Isle of Man, Ivory Coast, Jersey, Liberia, Mali, Mauritania, Saint Helena, Sao Tome and Principe, Senegal, Sierra Leone, Togo, and the United Kingdom. This makes GMT relevant well beyond the UK, particularly for organizations coordinating with West Africa, Atlantic territories, and international operations that still publish schedules against UTC+0.

BST (British Summer Time) is used in Guernsey, Isle of Man, Jersey, and the United Kingdom. For companies with headquarters, legal entities, or customer operations in these jurisdictions, British Summer Time affects office opening hours, call center coverage, transport timetables, and same-day service cutoffs during the summer season.

For travel and communications, the GMT-to-BST difference often appears in UK flight schedules, ferry times, event listings, and broadcast programming. A traveler flying into the United Kingdom in summer, or a remote worker joining a London meeting from a GMT location such as Ghana or Iceland, needs to account for the one-hour shift so arrival plans, check-ins, and conference calls line up correctly.

Common GMT to BST Conversion Examples

British Summer Time is consistently one hour ahead of Greenwich Mean Time in this comparison. A simple way to read the relationship is that a GMT morning becomes a later BST morning: 9:00 GMT = 10:00 BST, while 12:00 GMT = 13:00 BST.

The same pattern continues through the afternoon and early evening. For example, 15:00 GMT = 16:00 BST and 18:00 GMT = 19:00 BST, which is useful when you are planning UK end-of-day approvals, customer support handoffs, or media deadlines that must match British Summer Time office hours.

These examples are particularly helpful for distributed teams that receive mixed calendar labels. If one person sees a project checkpoint in GMT and another works from a UK summer schedule in British Summer Time, the examples above make it clear that the British Summer Time participant will join one hour later by the clock.

Frequently Asked Questions

What is the time difference between GMT and BST?

BST (British Summer Time) is 1 hour ahead of GMT (Greenwich Mean Time). In the opposite direction, GMT is 1 hour behind BST, so a schedule shown in GMT needs a one-hour adjustment to match British Summer Time.

Is BST ahead of GMT or behind it?

British Summer Time is ahead of Greenwich Mean Time by 1 hour. For example, 9:00 GMT becomes 10:00 BST, which is why UK summer office hours appear one hour later than GMT-based schedules.

Why do GMT and British Summer Time both appear for the United Kingdom?

Greenwich Mean Time is the standard-time abbreviation, and British Summer Time is the daylight saving abbreviation used for the summer period. This means UK schedules can appear under either label depending on the season, which is why businesses, travelers, and event organizers need to confirm whether a timetable is listed in GMT or British Summer Time.

How do I convert GMT to British Summer Time quickly?

Use the one-hour difference shown on the comparison grid: British Summer Time is always 1 hour ahead of Greenwich Mean Time on this page. The examples are straightforward—12:00 GMT = 13:00 BST and 15:00 GMT = 16:00 BST—so you can compare meeting slots, support coverage, or departure times without manual guesswork.

Which countries use GMT and which use British Summer Time?

GMT is used in Burkina Faso, Gambia, Ghana, Guernsey, Guinea, Guinea-Bissau, Iceland, Ireland, Isle of Man, Ivory Coast, Jersey, Liberia, Mali, Mauritania, Saint Helena, Sao Tome and Principe, Senegal, Sierra Leone, Togo, and the United Kingdom. British Summer Time is used in Guernsey, Isle of Man, Jersey, and the United Kingdom, which is why the GMT versus British Summer Time comparison is most relevant for UK-linked scheduling during the summer season.

Is BST British Summer Time or Bangladesh Standard Time?

On this page, BST means British Summer Time (UTC+1). BST can also mean Bangladesh Standard Time (UTC+6), which is a different time zone entirely; for that meaning, see /time-converter/bst-bangladesh-time-zone.