CallataGuidesArea code 773
Where 773 is, how it is dialed, which carriers hold its numbers and how many of its codes are in use, from NANPA's 10/01/2026 files.
- State
- IL
- In service
- 1996
- Assigned codes
- 786of 800 possible
- Carriers
- 22
About area code 773
NANPA lists 773 as an in-service geographic area code for Illinois, first put into service on October 12, 1996. It is an overlay: 773 and 872 cover the same territory, so neighbors on the same street can have different area codes. It is in the Central time zone.
| Item | Value |
|---|---|
| State | Illinois |
| In service since | October 12, 1996 |
| Assigned by NANPA | February 29, 1996 |
| Overlay | Yes, with 872 |
| Parent area code (NANPA) | 312 |
| Time zone | Central |
| Local calls within the code | 1 plus ten digits |
| Assigned central office codes | 786 |
| Rate centers with codes | 11 |
| Carriers holding codes | 22 |
| Pooled codes | 485 |
| Codes assigned since 2020 | 20 |
| Relief planning in progress | No |
Source: NANPA NPA report and utilized central office code file, both dated 10/01/2026.
Cities and towns in area code 773
773 holds 8.8% of the 8,977 central office codes assigned in Illinois, the 4th most of the state's 17 codes. None of its rate centers could be matched to a Census place name. Each place page lists the exact prefixes and carriers for that town.
How calls are dialed in 773
According to NANPA's dialing-plan data, local calls within 773 are dialed as 1 plus ten digits and toll calls as 1 plus ten digits. Because local calls need the area code, business cards, signage and website copy should always show the full ten-digit number.
Carriers with 773 numbers
22 carriers hold the 786 central office codes assigned in 773. Illinois Bell Tel CO has the most, with 257 (33%). 485 of the codes (62%) are pooled, meaning the code holder shares blocks of 1,000 numbers with other carriers instead of using all 10,000 itself. The code holder is not necessarily the carrier serving a given number today, since numbers can be ported between providers.
| Carrier (NANPA operating company) | Exchanges | Share |
|---|---|---|
| Illinois Bell Tel CO | 257 | 33% |
| T-mobile USA, INC. | 169 | 22% |
| New Cingular Wireless PCS, LLC - Il | 84 | 11% |
| Cellco Partnership d/b/a Verizon Wireless - Il | 59 | 7.5% |
| Mcimetro Access Transmission Services LLC | 38 | 4.8% |
| Level 3 Communications, LLC - Il | 36 | 4.6% |
| Paetec Itel, LLC | 33 | 4.2% |
| Teleport Communications America, LLC - Il | 23 | 2.9% |
| Onvoy, LLC | 16 | 2.0% |
| Spok, INC. | 13 | 1.7% |
| First Communications, LLC | 11 | 1.4% |
| RCN Telecom Services of Illinios, INC. - Il | 9 | 1.1% |
Carrier names are the operating company (OCN) names on NANPA's utilized central office code file dated 10/01/2026. A carrier holding a code may port numbers to other carriers.
Local calling areas in 773
NANPA assigns each central office code to a rate center, the local calling area that decides whether a call is local or toll. 773 has codes in 11 rate centers. Rate center names in the file are abbreviations; where one matches a Census place, the table links to that city's local-number page.
| Rate center (NANPA) | Place | Codes |
|---|---|---|
| CHICGOZN03 | not matched | 170 |
| CHICGOZN01 | not matched | 124 |
| CHICGOZN02 | not matched | 79 |
| CHICGOZN07 | not matched | 78 |
| CHICGOZN04 | not matched | 75 |
| CHICGOZN10 | not matched | 72 |
| CHICGOZN06 | not matched | 56 |
| CHICGOZN08 | not matched | 45 |
| CHICGOZN05 | not matched | 41 |
| CHICGOZN09 | not matched | 26 |
| CHICGOZN11 | not matched | 20 |
Number supply in 773
An area code has 800 possible central office codes that start with 2 through 9, a few of which are reserved (such as N11 service codes and 555). 786 are assigned in 773, 98% of 800. 20 were assigned in 2020 or later.
| Decade assigned | Exchanges | Share |
|---|---|---|
| 2000s | 195 | 85% |
| 2010s | 14 | 6.1% |
| 2020s | 20 | 8.7% |
Assignment dates as recorded in NANPA's utilized code file; codes without a recorded date are excluded.
Getting a 773 number for your business
Callata Office costs $99 per month for up to 5 people, and each additional user is $20 a month. That covers up to 3 local numbers, calling from a browser or your cell, transcribed voicemail, recorded calls with AI summaries, after-hours routing and E911 on each number.
Porting a number you already use in area code 773 is free, and business texting is available once the carrier registration (10DLC) is approved; the registration carries a one-time $49 fee. Which specific numbers are open in a given area code depends on carrier inventory at the time you sign up.
AI agents are optional: an AI receptionist or scheduler can pick up when the team is busy or closed, take a message, send a text or email, or transfer the call. They draw on prepaid AI minutes ($0.25/minute), disclose that they are AI, and outbound AI calls require prior consent and are limited to 8am–9pm.
Frequently asked questions
Where is area code 773?
773 is a geographic area code in Illinois.
What time zone is area code 773 in?
NANPA lists 773 in the Central time zone.
When did area code 773 go into service?
NANPA records an in-service date of October 12, 1996. The code was assigned on February 29, 1996.
Is 773 an overlay area code?
Yes. It shares its territory with 872.
Can my business get a 773 phone number?
Callata includes up to 3 local numbers on its $99/month plan (5 users included). Which 773 numbers are open depends on carrier inventory when you choose, and you can port an existing number for free.