GMT to UTC Time Zone Converter
This converts London time (GMT in winter, BST in summer) to UTC, the fixed clock the rest of the world measures against. In winter the two line up exactly; in summer London jumps an hour ahead, so it runs an hour in front of UTC. The tool handles that switch for you based on the date you pick.
Enter a date and time to convert.
Daylight saving is applied automatically for the date you pick. Labels like PST/EST name the zone (Pacific/Eastern); the real abbreviation shifts to PDT/EDT during daylight saving, and gmt here means London (GMT in winter, BST in summer) while utc stays fixed.
The time difference
The gap is seasonal because London observes daylight saving and UTC does not. In winter London is on GMT and matches UTC exactly — a 0-hour gap. In summer London moves to British Summer Time and runs 1 hour ahead of UTC, so the same London clock reads one hour later than UTC.
A worked example
Take 9:00 AM in London. On January 15, 2026 (winter), that is 9:00 AM UTC — identical, because London is on GMT. On July 15, 2026 (summer), London is on BST, so 9:00 AM London is 8:00 AM UTC, an hour earlier.
Daylight saving & the abbreviation caveat
"GMT" here is really London's clock: GMT in winter, BST (British Summer Time) from late March to late October. London springs forward on March 29 and falls back on October 25, 2026. UTC, by contrast, is a fixed standard that never shifts. So the two agreeing in January but differing by an hour in July isn't a mistake — it's London moving while UTC stays still. The converter tracks this automatically for whatever date you choose.
When you'll use it
Handy when a server log, flight schedule, or online meeting is stamped in UTC and you need it in London terms — or the reverse. Developers, pilots, and anyone coordinating across borders lean on UTC as the neutral baseline, and this tells you exactly how far London sits from it on any given day.
Frequently asked questions
Are GMT and UTC the same thing?
In winter, yes — London sits at UTC+0, so the clocks read the same. But GMT here means London's clock, and from late March to late October London moves to British Summer Time (BST), one hour ahead of UTC. UTC itself never moves.
Why does the gap change during the year?
UTC never observes daylight saving, but London does. When London springs forward in late March, its clock pulls an hour ahead of UTC until it falls back in late October.
Does UTC ever change for daylight saving?
No. UTC is a fixed reference and stays put all year. Any change you see in this conversion comes entirely from London's summer shift.