Convert GMT (Greenwich Mean Time) to PDT (Pacific Daylight Time)

Best time to schedule a meeting

Standard 9–5 working hours overlap for 1 hour: 4:00 PM–5:00 PM GMT (9:00 AM–10:00 AM PDT). Schedule meetings inside that window.

GMT to PDT conversion table

About GMT

Greenwich Mean Time (GMT) is UTC+0. It is used in the UK and Ireland in winter, Portugal, Iceland and much of West Africa.

The trap with GMT is that the United Kingdom is not on it for most of the year. From late March to late October the UK runs BST, UTC+1, so a meeting agreed "10am GMT" with a London colleague in July is an hour out unless both parties meant the abbreviation literally. Broadcasters and airlines avoid the ambiguity by saying UTC. GMT itself is fixed at UTC+0 and does not shift; it is the UK's clocks that move away from it and back.

About PDT

Pacific Daylight Time (PDT) is UTC−7. It is used in Los Angeles, San Francisco and Seattle from March to November.

Pacific Daylight Time is UTC−7, the summer clock for Los Angeles, San Francisco, Seattle and Vancouver. It is the zone most product launches and software release times are quoted in, and it is worth converting rather than eyeballing: PDT is eight hours behind British Summer Time, not seven, because both sides have moved.

Does this gap change with the seasons?

This gap is seasonal. The abbreviations themselves are fixed offsets, but the region on GMT switches to BST (UTC+1) from late March to late October, and the region on PDT switches to PST (UTC−8) from November to March. So the 7-hour figure on this page is correct for the part of the year when both places are actually on these abbreviations, and changes by an hour outside it.

Because both sides shift, there are also short windows each spring and autumn when one has changed and the other has not — the two regions do not switch on the same date. A recurring meeting set during one of those windows is an hour out for a week or two, which is the most common way this catches people.

This is the reason scheduling systems store an IANA zone such as Region/City rather than an offset or an abbreviation: the zone knows its own rules and the offset does not.

Frequently asked questions