437 Area Code – Toronto, Ontario: Location, Time Zone & History

Toronto's phone numbers had already outgrown a single area code by the time 437 arrived on March 25, 2013. It was the second overlay layered onto the city's original 416, following 647, after the Canadian Numbering Administrator forecast that the two existing codes would run out of numbers by mid-2015. The Canadian Radio-television and Telecommunications Commission approved the addition under Telecom Decision 2011-436, and at the same time set aside code 387 as a future relief option for the complex.

Unlike 416, which still carries a certain cachet among longtime residents as Toronto's original area code, 437 numbers are newer assignments that don't carry the same status association. The city's economy spans finance and banking, media and entertainment, technology and startups, film and television production, and higher education and research — sectors that have all fed continued demand for phone numbers in the area.

The numbering plan area covers Toronto and its surrounding districts of Scarborough, North York, Etobicoke, East York, and York. Growth pressure on the complex continued after 437's introduction: the CRTC revisited relief planning in 2017, and a further overlay, area code 942, went into service in 2025.