Area code 403 — Alberta
Southern Alberta including Calgary. Original assignment, in service since 1947.
At a glance
- Country
- Canada
- Province / territory
- Alberta
- Service area
- Southern Alberta including Calgary
- Time zone
- Mountain Time (MST/MDT, UTC-7/-6) · current offset -06:00
- Type
- Original
- In service since
- 1947
- Country code
- +1 (NANP)
Map
Cities served by 403
Related & overlay area codes
Area code 403 shares geography with 3 other codes serving the same region. A call placed inside this overlay must dial all 10 digits regardless of which code your own line uses.
Carriers operating in 403
The following national and regional telecommunications carriers hold central office (CO) code assignments within numbering plan area 403. Number portability means a phone number originally issued by one carrier may now ride on another carrier's network.
About area code 403
Area code 403 is a Canadian numbering plan area covering Southern Alberta including Calgary. It was placed into service in 1947 as one of the original Canadian assignments, and today operates under the Mountain Time (MST/MDT, UTC-7/-6) time zone.
Numbers in the 403 NPA are issued in central office (CO) blocks of 10,000 to local exchange carriers, who then assign them to subscribers. Because Canada uses a competitive carrier model under CRTC oversight, multiple carriers — both incumbent and competitive — hold blocks within 403. The current carrier of record for any specific number can be looked up via the Canadian Local Number Portability Consortium, but the originally issued carrier is no longer a reliable signal of who actually serves that line.
If you receive a call from a number beginning with 403, the caller is either physically located in or has historically been associated with Southern Alberta including Calgary. The same applies to overlay codes 587, 825, 368: any of these area codes can correspond to a phone in the same geography, and many households carry numbers from two or three different overlays simultaneously across landlines and mobile devices.
To call a number in 403 from outside Canada and the United States, dial your country's international access prefix, then +1 403 followed by the 7-digit local number. Within the NANP, simply dial 1 followed by all 10 digits — or just the 10 digits if you are also located in an overlay region where 7-digit local dialling is no longer permitted.
Frequently asked questions
Where is area code 403?
Area code 403 serves Southern Alberta including Calgary in Alberta, Canada.
What time zone is 403?
Numbers in 403 are in the Mountain Time (MST/MDT, UTC-7/-6) time zone.
Is 403 a toll-free or mobile-only code?
No. Canadian area codes are geographic — they apply to both landline and mobile numbers in Southern Alberta including Calgary. Toll-free codes in the NANP (800, 833, 844, 855, 866, 877, 888) are a separate category.
Why do I see calls from 403 if I do not know anyone there?
Two reasons. First, mobile portability: someone who moved away from Alberta can keep their 403 number anywhere in the world. Second, scam callers frequently spoof Canadian area codes to appear local. If you do not recognise the number, it is generally safe to let it go to voicemail.