Toronto is UTC−4 (EDT) / UTC−5 (EST). London is UTC+0 (GMT) / UTC+1 (GMT+1). London is currently 5 hours ahead of Toronto.
Best times to meet (Toronto local time): 9:00 AM — 2:00 PM in London; 10:00 AM — 3:00 PM in London; 11:00 AM — 4:00 PM in London.
Times shown in Toronto local time → London local time. Based on business hours 09:00–17:00.
Toronto observes Eastern Time: UTC−5 (EST) in winter and UTC−4 (EDT) in summer, following the same schedule as New York and the US East Coast. Canada adopted standard time nationally following the same railway-driven pressures as the United States, with the Railway Committee of the House of Commons standardising time zones in 1918. Toronto is Canada's largest city, its financial capital, and home to the Toronto Stock Exchange (TSX), which opens and closes at the same times as the New York Stock Exchange due to the shared timezone.
The synchronisation of Toronto and New York time is economically significant: Bay Street (Toronto's financial district) and Wall Street effectively operate as a single North American market window. Toronto is 5 hours behind London in winter, making early-morning London calls (08:00 GMT = 03:00 EST) impractical, while afternoon London calls (17:00 GMT = 12:00 EST) fall comfortably within Toronto business hours. The Canadian DST rules mirror US federal rules exactly, meaning Toronto and New York never have a temporary offset difference due to mismatched clock-change dates.
Canada's geography spans six time zones, from Newfoundland Time (UTC−3:30) to Pacific Time (UTC−8), making pan-Canadian scheduling a notable challenge for national companies. Toronto's Eastern Time creates a 3-hour spread between Toronto and Vancouver (PT), meaning a 09:00 Toronto call begins at 06:00 in Vancouver — before most people are awake. Internationally, Toronto's UTC−5 winter offset places it equidistant (in hours) between London (+5 hours ahead) and Los Angeles (−3 hours behind), making it a convenient scheduling hub for trans-Atlantic and trans-continental North American meetings.
London operates on Greenwich Mean Time (GMT, UTC+0) in winter and British Summer Time (BST, UTC+1) from late March to late October. The city sits at the Prime Meridian — longitude 0° — established at the Royal Observatory in Greenwich in 1884 when the International Meridian Conference adopted Greenwich as the world's reference point for time and longitude. The GMT standard was already in widespread use because of Britain's dominance in maritime navigation and the railway network, which demanded a single national time to replace the patchwork of local times that differed by minutes from town to town.
The UK introduced Daylight Saving Time during World War I in 1916, following Germany's lead, to reduce coal consumption by extending evening daylight. Today DST is governed by EU rules (retained in UK law post-Brexit), meaning the clocks change on the last Sunday of March and October. London is one of the world's most important financial centres: the London Stock Exchange opens at 08:00 GMT and closes at 16:30, overlapping with Asian market closes in the morning and US market opens in the afternoon — a position that helps make London the largest foreign-exchange trading centre on earth.
Because London is UTC+0 in winter, it serves as a natural reference point for international scheduling. A meeting at "noon UTC" is noon in London from November to March. The city is 5 hours ahead of New York (EST) in winter and 8 hours behind Tokyo (JST), making it the pivot of East–West business communication.
London is currently 5 hours ahead of Toronto.
When it is 12:00 noon in Toronto, it is 17:00 in London (based on current offsets — verify during DST transitions).
Toronto observes DST, changing from EDT to EST. London observes DST, changing from GMT to GMT+1.