GMT Converter
Convert between GMT and any time zone
GMT to local and back, with the distinction from UTC spelled out — and a warning for the British summer, when a clock labelled GMT is actually an hour ahead of it.
Questions people ask
The things that come up about gmt converters, answered plainly.
Is GMT the same as London time?
Only in winter. From late March to late October the UK observes British Summer Time, which is UTC+1 — so a London clock reading 13:00 in July is 12:00 GMT. Calling UK time 'GMT' year-round is the single most common time-zone error in British scheduling.
Should I use GMT or UTC in software?
UTC, always. GMT is ambiguous — some systems use it to mean the Europe/London zone, complete with summer time — and UTC is not.
Related tools
Convert between zones, watch a board of cities, and find the hour that suits everyone.
UTC ConverterUTC in, local out, or the other way round — with the offset that applied on that date, which is not always the one that applies today.
GMT Offset CalculatorThe offset in GMT terms, with the caveat this whole category turns on: GMT and UTC agree, but 'GMT' as a clock label in Britain does not agree with either for half the year.
Time Zone ConverterOne instant, two clocks. Pick the zones, enter a time, and see what it reads in the other — with the date shift, the offset difference and any daylight-saving trap called out.
DST CheckerWhether a zone is on summer time right now, when it next changes, and the exact instant of the change — found by search, to the millisecond.