Area codes 416, 647, and 437 are telephone area codes in the North American Numbering Plan (NANP) for the city of Toronto, Ontario, Canada. Area code 416 is one of the original North American area codes created by the American Telephone and Telegraph Company (AT&T) in 1947. Area codes 647 and 437 are additional area codes for the same numbering plan area (NPA), forming an overlay numbering plan.

The incumbent local exchange carrier in the numbering plan area is Bell Canada. Almost all Toronto Bell Canada landlines have area code 416, with 647-numbers allocated disproportionately to a growing mobile telephone market and to competitive local exchange carriers, such as cable and voice-over-IP services. Telephone numbers are portable, with few exceptions for specific services such as pocket pagers.

The competitive local exchange carriers in numbering plan area are Rogers Communications, Telus, and some independent companies.

Demand for telephone numbers with area code 416 for mobile, foreign exchange and voice over IP service in the 905-suburbs (Durham, Peel, York and Halton regions) has elevated the local significance of these numbers as their local calling area is a superset of that of a suburban number.

Toronto's original manual telephone exchanges were recognized by an exchange name and a block of four-digit line numbers. The "GRover exchange" at Kingston Road and Main Street in East Toronto became the first Canadian dial exchange in 1924. Montréal got its first dial telephones one year later. The numbers were dialled as two letters and four digits (2L+4N). Grover 1234 was dialled GR-1234 (or 47-1234). Conversion to seven-digit (2L+5N) format began in 1951, and continued until the introduction of direct distance dialling (DDD) in 1958.

Area code 416 was one of the 86 original North American area codes, assigned by the American Telephone and Telegraph Company (AT&T) for Operator Toll Dialing in 1947. It comprised most of the populous Golden Horseshoe region in southern Ontario, from Colborne to Niagara Falls to Kitchener-Waterloo. It was almost completely surrounded by Ontario's other area code, 613. Ontario and Quebec were the only provinces to be assigned multiple area codes at the inception of the continent-wide telephone numbering plan.

Area code 416 has been split twice. The first came in 1953, when the western portion of 416 (including Kitchener) was combined with the southern portion of area code 613 to form area code 519. This left 416 largely co-extensive with the area that is generally reckoned as the core of the Golden Horseshoe. Despite rapid growth in the Greater Toronto Area (GTA), this configuration remained for 40 years.

By the late 1980s, however, 416 was close to exhaustion because of the GTA's continued growth and Canada's inefficient number allocation system. Canada does not use number pooling as a relief measure. All competing carriers are assigned 10,000-number blocks, which correspond roughly to a single prefix, in each rate centre in which it plans to offer service, regardless of its actual subscriber count. Most rate centres do not need nearly that many numbers to serve their customers, but a number cannot be allocated elsewhere once it has been assigned to a carrier and rate centre, resulting in thousands of wasted numbers. The problem was less severe in the Golden Horseshoe than in other areas of Canada since then, as now, numbers tended to be used up fairly quickly because of the area's dramatic growth.

The GTA's rapid growth in telecommunication services, and the proliferation of cell phones, fax machines, and pagers, demanded more central offices, with another area code for the Golden Horseshoe soon becoming necessary. This resulted in a second split of 416 when, in October 1993, the area code's numbering plan area was reduced to its current size, consisting only of the municipalities constituting Metropolitan Toronto (East York, Etobicoke, North York, Toronto, Scarborough, and York). The rest of the former 416 numbering plan area, consisting of the Golden Horseshoe outside Metropolitan Toronto (the Niagara Peninsula, the regional municipalities of Durham, Halton, Hamilton–Wentworth, Peel, and York, and parts of Northumberland County) were assigned area code 905. Although 905 was introduced in 1993, permissive dialing of 416 for the Golden Horseshoe beyond Metropolitan Toronto continued until March 1994.

With the amalgamation of Metropolitan Toronto into the "megacity" of Toronto in 1998, 416 became the only Canadian area code to serve just one rate centre and just one city. Many of Canada's larger cities, especially "megacities" that have been created from mergers of previously separate cities, are split between multiple rate centres that have never been amalgamated. Toronto is an exception and has been a single rate centre, which is by far Canada's largest, since 1977, with the merger of the historical Agincourt, Don Mills, Islington, New Toronto, Scarborough, West Hill, Weston, and Willowdale exchanges into the Toronto exchange.

The 1993 split had been intended as a long-term solution for Canada's largest toll-free calling zone. Within five years, however, 416 was once again close to exhaustion. Toronto's size and status as a single rate centre have caused numbers to tend to be used up fairly quickly. Therefore, the number allocation problem was not nearly as serious as in other Canadian cities that are split between multiple rate centres. Splitting Toronto between two area codes, a solution adopted in the United States for cities like New York City, Chicago and Los Angeles, was ruled out because of the area's high population density and the lack of a suitable boundary along which to split. Another option was the conversion to an overlay plan for 416. Overlays were a new concept that was somewhat controversial because of the requirement for ten-digit dialling. Bell and other telephone companies pressed for an overlay since they wanted to spare their customers the expense and burden of having to change telephone numbers, which would have required a massive reprogramming of cellular telephones. Also, it would have been extremely difficult to split Toronto since it is a single rate centre. Ultimately, the decision was made to implement an overlay.

On March 5, 2001, 416 was overlaid with area code 647, creating Canada's first overlay. The implementation of 647 made ten-digit dialling mandatory in Toronto. Within a decade, both 416 and 647 were close to exhaustion once again. A new overlay area code, 437, started operation on March 25, 2013. That effectively allocates 24 million numbers to a city of 2.5 million people.

Area code 942 is scheduled for addition to the 416/647/437 overlay on April 26, 2025. Area code 387 has been reserved for Toronto's future use.

Since the implementation of area code 647, overlays have become the preferred solution for exhaustion relief in Canada, as it does not require renumbering existing subscriber accounts. As of April 28, 2023, only three Canadian area codes (709, 807, and 867) are still single-code areas, without overlay, still allowing seven-digit dialing for local calls.

A 2020 exhaust analysis by the NANPA projects exhaustion in 2025 for central office prefixes in the numbering plan area. In April 26, 2025, the CTRC will introduce area code 942 for Toronto.

Toronto is the centre of the largest local calling area in Canada, and one of the largest in North America. As of 2013, the following points in area code 905 were a local call to 416 in Toronto: Ajax-Pickering, Aurora, Beeton, Bethesda, Bolton, Brampton, Caledon East, Campbellville, Castlemore, Claremont, Georgetown, Gormley, King City, Markham, Milton, Mississauga (rate centres Clarkson, Cooksville, Malton, Nobleton, Port Credit and Streetsville) Oak Ridges, Oakville, Palgrave, Richmond Hill, Schomberg, Snelgrove, South Pickering, Stouffville, Thornhill, Tottenham, Unionville, Uxbridge, Vaughan (rate centres Kleinburg, Maple and Woodbridge) and Victoria. Caledon in area code 519 is also a local call to Toronto. Many of these suburban areas are long-distance to each other, particularly, but not exclusively, those which are across Toronto from each other (i.e., north versus east versus west of Toronto).

In the Greater Toronto Area, the terms the 416 is also used to describe the area within Toronto proper, and Toronto residents are called 416ers. The suburbs are referred to as the 905 or the 905 belt, and suburbanites are called 905ers (in this use the term does not include the more distant parts of area code 905, such as Niagara Falls).

The 647 area code does not carry the same strong geographic associations as it disproportionately contains nomadic services (such as mobile telephones and voice over IP); an incumbent Bell land line is hard-wired to a specific location in area 416, postal code M. Some have paid a premium for a true 416 number as the code gives the appearance of a local, long-established business instead of a new entrant.

On March 17, 1966, The Munsters episode "A Visit from Johann" depicted a person-to-person call to a Happy Valley Lodge in the 416 area code. A hamlet of Happy Valley exists in King Township, in 416 at the time, but now in 905 (as part of York Region).

In 1994, food delivery chain Pizza Pizza obtained a Canadian registered trademark on its 416 telephone number, 967–1111, which had featured in distinctive radio advertising jingles since the 1970s.

Toronto rapper Maestro Fresh Wes rendered homage to the area code in his 1998 song "416/905 (TO Party Anthem)". Rapper Drake has a tattoo of the number on his rib to symbolize Toronto as his birthplace. Drake has also released his fourth studio album, titled Views, referring to the 416 and 647 area codes. His album picture is of him sitting on top of the CN Tower in Toronto.

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All central office codes reside within the rate centre of Toronto. In some cases, 416 prefixes are available to wire centres outside Toronto city limits which serve Toronto subscribers (such as MALTON22 in Mississauga, which serves an airport hotel strip in Toronto).

Toronto's original manual telephone exchanges used exchange names, each serving a block of four-digit telephone numbers. The GRover exchange at Kingston Road and Main Street in East Toronto was the first Canadian dial exchange in 1924. Montréal in Quebec got its first dial telephones one year later. The numbers were dialled with two letters and four digits (2L-4N). For example, GRover 1234 was dialled GR1234 (or 471234). Conversion to seven-digit (2L-5N) format began in 1951, and continued up to the introduction of direct distance dialling (DDD) in 1958.

Toronto numbers that were converted from 2L-4N format, or from manual service, include:

• 416–363, 364, 366, 368 (EMpire 3,4,6,8) were ADelaide, ELgin, PLaza and WAverly in the Adelaide St (Queen West) area west of downtown. These were the first to be lengthened to 2L-5N in 1951–1953.
• 416-861 (UNiversity 1) was TRinity exchange in the Adelaide St (Queen West) area west of downtown (lengthened to 2L-5N in 1955).
• 416–921, 922, 923, 924 (WAlnut 1,2,3,4) were RAndolph, KIngsdale, MIdway and PRincess (lengthened to 2L-5N in 1954) in the Annex.
• 416–691, 694, 699 (OXford 1,4,9) were HOward, GRover, OXford (lengthened to 2L-5N in 1955) in East Toronto. These numbers usually relate to the Beaches and Upper Beaches neighbourhoods or to Crescent Town in East York.
• 416–461, 463, 465, 466 (HOward 1,3,5,6) were RIverdale, GErrard, GLadstone, HArgrave east of downtown (lengthened to 2L-5N in 1957).
• 416–483, 485, 488, 489 (HUdson 3,5,8,9) were MOhawk, MAyfair (lengthened to 2L-5N in 1958) and HUdson, HYland (lengthened to 2L-5N in 1953); these served the Eglinton area, then the northernmost point on the TTC subway (1954).
• 416–782, 783 (RUssell 2,3) were ORchard, REdfern (lengthened to 2L-5N in 1958) in the Willowdale/Weston areas in the north of the city.
• 416–762, 766, 767, 769 (ROger 2,6,7,9) were MUrray, ROdney, LYndhurst, JUnction (lengthened to 2L-5N in 1955) in the Runnymede/Toronto Junction area in the west end.
• 416–531, 532, 533, 534, 535, 536 (LEnnox 1,2,3,4,5,6) were MElrose, LAkeside, KEnwood, OLiver, LLoydbrook, LOmbard in the Dufferin Street area west of downtown (lengthened to 2L-5N in 1956).

Additional named exchanges were created (as 2L-5N) in the late 1950s to accommodate expansion into then-growing suburbs such as Don Mills (GArden), Agincourt (AXminster/CYpress), Islington (BElmont/CEdar), New Toronto (CLifford), Scarborough (AMherst, PLymouth), West Hill (ATlantic), Weston (CHerry, MElrose) and Willowdale (BAldwin/ACademy). Exchange names were phased out in 1961–1966 in favour of plain seven-digit numbers.

• List of Ontario area codes
• List of North American Numbering Plan area codes

• NANP Administrator (October 19, 1989). "Planning Letter(s): IL-89/010-048" (PDF). www.nationalnanpa.com. NANP Administrator. Retrieved January 11, 2023. NANP - Interchangeable Central Office Codes in the Toronto, Ontario, Canada 416 NPA

• Area code map of Canada
• CNA exchange list for area code 416
• CNA exchange list for area code 647
• CNA exchange list for area code 437

Ontario area codes: 416/437/647, 519/226/548/382, 613/343/753, 705/249/683, 807, 905/289/365/742

	North: 905/289/365/742
West: 905/289/365/742	416/437/647	East: 905/289/365/742
	South: Lake Ontario 905/289/365/742

43°41′13″N 79°23′35″W / 43.687°N 79.393°W / 43.687; -79.393