BST to GMT Time Converter
Instantly convert British Summer Time (BST) to Greenwich Mean Time (GMT). See the exact time difference, date changes, and 12/24-hour formats — all in seconds.
BST to GMT Calculator
Convert British Summer Time to Greenwich Mean Time
Enter the time in BST (UTC+1). Use the 24-hour format.
Converted Time
BST to GMT calculation results
Enter a time in BST above, then click Convert to GMT to see the exact Greenwich Mean Time equivalent.
UK Time Zones FAQ
Everything you need to know about British Summer Time, Greenwich Mean Time, and how the UK clock changes work.
GMT (Greenwich Mean Time) is the standard time zone for the UK during the winter months, corresponding to UTC+0. BST (British Summer Time) is the daylight saving time used in the summer, which is UTC+1. Therefore, BST is exactly one hour ahead of GMT.
BST starts at 01:00 GMT on the last Sunday in March, when the clocks go forward by one hour to 02:00. It ends at 02:00 BST on the last Sunday in October, when the clocks go back by one hour to 01:00 GMT.
To convert BST to GMT, you simply subtract one hour. For example, if it is 14:00 (2:00 PM) in BST, it is 13:00 (1:00 PM) in GMT. The only exception is between 00:00 and 00:59 BST, which converts to 23:00 to 23:59 GMT on the previous day.
No. The UK only uses GMT during the winter months. From late March to late October, the UK switches to British Summer Time (BST), which is one hour ahead of GMT.
GMT (Greenwich Mean Time) and UTC (Coordinated Universal Time) are effectively the same for civil timekeeping, both representing UTC+0. BST is the daylight saving time used in the UK, which is UTC+1. While GMT is a time zone, UTC is a time standard.
Train and flight schedules are typically published in local time. When the clocks go forward in March, services may appear to start an hour later relative to the previous day, but they are running to the correct local schedule. Airlines and rail operators adjust their timetables accordingly, so your ticket time remains valid in the local time zone.
BST was introduced by the Summer Time Act 1916, following the efforts of William Willett, who proposed daylight saving time to make better use of daylight during the evenings and to save energy during the First World War.
England, Scotland, Wales, and Northern Ireland all use GMT in winter and BST in summer. The Republic of Ireland uses Irish Standard Time (IST) in summer, which is also UTC+1, meaning the entire island is on the same time during the summer months, despite having different legal names for the time zone.