GMT vs BST: Understanding the Key Time Zone Difference
GMT is the standard time zone based on the meridian at Greenwich, UK; BST is the UK’s daylight-saving offset, one hour ahead of GMT.
People often write “GMT” all year, forgetting the UK clocks jump forward in spring. Flight trackers and calendar invites then feel off by an hour, making the mix-up frustratingly common.
Key Differences
GMT stays fixed. BST shifts clocks forward in spring and back in autumn. When BST is active, 12:00 GMT is 13:00 BST.
Which One Should You Choose?
If you’re scheduling with the UK between late March and October, use BST. Outside those months, stick with GMT.
Examples and Daily Life
Your London conference call set for 14:00 “GMT” in July will actually start at 15:00 local time—because London’s on BST.
Is the UK ever on GMT in summer?
No. During summer the UK observes BST, so clocks are one hour ahead of GMT.
Does GMT ever change?
GMT itself never changes; only regions switch to BST or other offsets.
How do I check which is in use?
Look at any world-clock app; if London shows a time one hour ahead of GMT, BST is active.