How many hours is GMT behind BST?
As abbreviations, BST is always 1 hour ahead of GMT: GMT is UTC+0 and BST is UTC+1. To convert, add 1 hours.
When the GMT to BST time difference changes
For most of the year BST is 1 hour ahead of GMT. From 25 October to 31 December 2026, BST and GMT show the same time instead, because the two places change their clocks on different dates. Meetings booked by the usual gap land an hour off in those weeks.
| Dates | BST vs GMT | Length |
|---|---|---|
| 29 March 2026 to 24 October 2026 | 1 hour ahead | 210 days |
| 25 October 2026 to 31 December 2026 | same time | 68 days |
| 1 January 2027 to 27 March 2027 | same time | 86 days |
| 28 March 2027 to 30 October 2027 | 1 hour ahead | 217 days |
| 31 October 2027 to 31 December 2027 | same time | 62 days |
Best time for a meeting between GMT and BST
- When BST is 1 hour ahead of GMT: 7 shared office hours, 09:00 to 16:00 in GMT (10:00 to 17:00 in BST).
- When BST and GMT show the same time: 8 shared office hours, 09:00 to 17:00 in GMT (09:00 to 17:00 in BST).