GMT to CST
London to Shanghai.
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All date & timeQuestions
What time is CST when it is 12:00 GMT?
20:00. China Standard Time is 8 hours ahead of Greenwich Mean Time in January and 7 hours ahead of it in July. The gap moves because London observes daylight saving and Shanghai does not, so the difference between them is not a fixed number. There is no hour of the standard working day that is inside 9-to-5 in both London and Shanghai. One side has to take the call outside office hours, so it is worth agreeing which.
Is the difference between GMT and CST the same all year?
No, and this is the pair where that matters. China Standard Time is 8 hours ahead of Greenwich Mean Time in January and 7 hours ahead of it in July. The gap moves because London observes daylight saving and Shanghai does not, so the difference between them is not a fixed number. Booking a recurring call across these two and assuming one number will drift by an hour twice a year — check the date, not just the zones.
What do GMT and CST actually stand for?
GMT is Greenwich Mean Time, the zone covering London, currently UTC+0 in January. CST is China Standard Time, covering Shanghai, at UTC+8. GMT and UK time are the same thing only in winter. From late March to late October London runs on British Summer Time, an hour ahead of GMT, so a meeting booked as 'GMT' with someone in London is an hour out for most of the year.
Anything worth knowing about China Standard Time?
The whole of China runs on a single zone, UTC+8, despite spanning five geographic ones — so the sun rises after 10am in western Xinjiang in winter. No daylight saving anywhere in the country.
When is a good time to call between London and Shanghai?
There is no hour of the standard working day that is inside 9-to-5 in both London and Shanghai. One side has to take the call outside office hours, so it is worth agreeing which. If the call has to happen outside that, the fairer arrangement is usually to alternate which side takes the awkward hour rather than always asking the same one.
How it works, and more about gmt → cst
The difference, and whether you can rely on it
In January, China Standard Time is 8 hours ahead of Greenwich Mean Time — UTC+0 against UTC+8. In July it is 7 hours ahead instead. That is the part worth carrying away: this is not a pair you can memorise a single number for.
Why the gap moves
London observes daylight saving; Shanghai does not. So the clocks in one city move twice a year while the other stays put, and the distance between them changes with them. Any calculation you did in one season is wrong in the other. The converter above uses the date you give it rather than today’s offset, which is the only way to get a future meeting right when it falls on the other side of a changeover.
When you can both be at a desk
There is no hour inside 9-to-5 in both London and Shanghai. Whatever you schedule, one side is taking it outside working hours — so the useful question is not when to meet but who absorbs the inconvenience, and whether it alternates.
Reading the abbreviations literally will mislead you
GMT strictly means one fixed offset, but almost nobody uses it that way. People write it to mean the time in London, which shifts if that city observes daylight saving — and it does. This page follows the common usage rather than the strict one, because the strict reading gives an answer that is wrong for a good part of the year.
GMT and UK time are the same thing only in winter. From late March to late October London runs on British Summer Time, an hour ahead of GMT, so a meeting booked as 'GMT' with someone in London is an hour out for most of the year. The whole of China runs on a single zone, UTC+8, despite spanning five geographic ones — so the sun rises after 10am in western Xinjiang in winter. No daylight saving anywhere in the country.
Scheduling something recurring
For a one-off, the converter above is the whole job. For a standing meeting across these two zones, where the gap changes, it is worth putting the invitation in a calendar that stores the zone rather than the time — then the changeover is handled for you and nobody has to remember. If you are trying to find a slot across more than two places at once, the meeting planner shows a whole day at a glance instead.