Area code 403


Area code 403 is a telephone area code in the Canadian province of Alberta, encompassing the southern third of the province, including the Calgary area.
The 403 area code was one of the original 89 area codes assigned in 1947 in the contiguous United States and the then nine-province extent of Canada. It originally encompassed the whole province of Alberta, the Yukon and the western half of the Northwest Territories. It was the second-largest numbering plan area in the North American Numbering Plan, spanning more than one-ninth of the circumference of the planet from the 49th parallel north to the North Pole. On October 3, 1997, 403 was cut back to Alberta, when the territories were split off as their own separate area code, 867.
Within only a year, 403 was back to the brink of exhaustion due to Canada's number allocation system. Every local exchange carrier is allocated blocks of 10,000 numbers–corresponding to a single three-digit prefix–for every rate centre where they plan to offer service, even for the smallest hamlets. While most rate centres do not need nearly that many numbers, it is not possible to move a number from one rate centre to another. This resulted in thousands of wasted numbers, and the proliferation of cell phones and pagers–especially in Calgary and Edmonton–only exacerbated this.
On January 25, 1999, the northern two-thirds of Alberta, including Edmonton, was split into the new area code 780. Generally, everything from Red Deer, Lacombe and Ponoka southward stayed in 403. Permissive dialing of 403 continued across the province until May 18, 1999.
This was intended as a long-term solution, but within a decade 403 was close to exhaustion once again. To solve the problem, it was decided to implement area code 587 as a province-wide overlay. Optional provincewide 10-digit dialing began on June 23, 2008, and became mandatory on September 12, 2008. On September 20, 2008, Telus Mobility began assigning 587 numbers to new customers in Calgary and Edmonton.
The incumbent local exchange carrier in 403 is Telus; prior to 1997, the larger 403 included EdTel and Northwestel as incumbent LECs. Prior to 1990, Telus was known as Alberta Government Telephones, and was a department of the provincial government.

Communities included

976 calls require dialling 1 before any AB area code.
The projected exhaust date for Area Code 403 was March 2009. For more information see the . Two area codes, 587 and 825, have been reserved and the first one, 587, was introduced in September 2008. The 403 area code, simultaneously with area code 780, will be overlaid with the new area code, which will cover the entire province.