AEST to GMT
Sydney to London.
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All date & timeQuestions
What time is GMT when it is 12:00 AEST?
01:00. Greenwich Mean Time is 11 hours behind Australian Eastern Time in January and 9 hours behind it in July. The gap moves because the two change their clocks on different dates, so for a week or two each spring and autumn the usual difference is an hour out. There is no hour of the standard working day that is inside 9-to-5 in both Sydney and London. One side has to take the call outside office hours, so it is worth agreeing which.
Is the difference between AEST and GMT the same all year?
No, and this is the pair where that matters. Greenwich Mean Time is 11 hours behind Australian Eastern Time in January and 9 hours behind it in July. The gap moves because the two change their clocks on different dates, so for a week or two each spring and autumn the usual difference is an hour out. 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 AEST and GMT actually stand for?
AEST is Australian Eastern Time, the zone covering Sydney, currently UTC+11 in January. GMT is Greenwich Mean Time, covering London, at UTC+0. Southern hemisphere daylight saving runs October to April — the opposite half of the year to Europe and North America. So the gap between Sydney and London swings by two hours across the year, not one.
Anything worth knowing about Greenwich Mean Time?
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.
When is a good time to call between Sydney and London?
There is no hour of the standard working day that is inside 9-to-5 in both Sydney and London. 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 aest → gmt
The difference, and whether you can rely on it
In January, Greenwich Mean Time is 11 hours behind Australian Eastern Time — UTC+11 against UTC+0. In July it is 9 hours behind instead. That is the part worth carrying away: this is not a pair you can memorise a single number for.
Why the gap moves
Both Sydney and London put their clocks forward, but not on the same weekend. For a week or two each spring and autumn the usual difference is an hour out, which is long enough to miss a recurring meeting twice a year and never work out why. 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 Sydney and London. 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
AEST strictly means one fixed offset, but almost nobody uses it that way. People write it to mean the time in Sydney, 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.
Southern hemisphere daylight saving runs October to April — the opposite half of the year to Europe and North America. So the gap between Sydney and London swings by two hours across the year, not one. 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.
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.