The 428 area code is a new statewide overlay covering all of Connecticut. Unlike the state’s regional codes, 428 is not tied to one part of the state – it was introduced as relief across the entire existing 203/475 and 860/959 territories to keep Connecticut supplied with new phone numbers.
Quick Summary of the 428 Area Code
| Area Code | 428 |
| State | Connecticut (CT) |
| Region | Statewide Connecticut Overlay |
| Major Cities | Hartford, Bridgeport, New Haven, Stamford, Waterbury, Norwalk, Danbury, New Britain |
| Time Zone | Eastern Time (ET) – EST / EDT |
| Dialing Format | 10-digit dialing required |
Geographic Coverage
The 428 area code covers the entire state of Connecticut as a statewide overlay, spanning both the southwestern region served by 203 and 475 – including Bridgeport, New Haven, Stamford, Norwalk, Danbury, and Waterbury – and the northern and eastern region served by 860 and 959, including Hartford, New Britain, and the eastern shore. A 428 number can be issued anywhere in Connecticut.
Time Zone
The 428 area code observes Eastern Time (ET). Clocks follow Eastern Standard Time (UTC−5) in winter and shift to Eastern Daylight Time (UTC−4) from mid-March through early November. All of Connecticut is on Eastern Time. From the West Coast, this region is three hours ahead of Pacific Time, so a 9:00 AM call in California reaches a 428 number at 12:00 PM local time.
Tip: Business hours across the 428 region generally run 9:00 AM to 5:00 PM Eastern Time, Monday through Friday.
How to Dial a 428 Number
Because area code 428 operates as part of an overlay, 10-digit dialing is mandatory for every local and long-distance call. You must dial the full 10-digit number (428 + the seven-digit line number) even when calling a neighbor across the street. For international callers, dial your country’s exit code, then +1 (the North American country code), then 428, followed by the seven-digit local number.
Scam Alerts for the 428 Area Code
Like every U.S. area code, 428 has been used by scammers who spoof local numbers to appear trustworthy. Residents in Hartford, Bridgeport, New Haven, Stamford, Waterbury, Norwalk, Danbury, New Britain should stay alert to the following common tactics:
| Scam Type | What to Watch For |
|---|---|
| IRS / Tax Scams | Callers impersonating the IRS and threatening arrest over supposed unpaid taxes. |
| Utility Shut-off | Fake Eversource or United Illuminating callers demanding instant payment to keep your power on. |
| Tech Support Fraud | Pop-ups or calls claiming your computer is infected and asking for remote access. |
| Prize / Lottery Scam | Calls saying you won a prize but must pay a “fee” or “tax” to claim it. |
If you receive a suspicious call from a 428 number, take these steps to protect yourself:
- Do not share personal information such as Social Security numbers, bank details, or passwords over the phone.
- Hang up and verify by calling the organization back using an official number from its website.
- Report the call to the FTC at reportfraud.ftc.gov and to the Connecticut Department of Consumer Protection.
- Block the number and consider registering with the National Do Not Call Registry.
Red Flag: Legitimate agencies such as the IRS, Social Security Administration, or your local utility company (Eversource or United Illuminating) will never demand immediate payment by gift card, wire transfer, or cryptocurrency. Any 428 caller making such a demand is a scammer.
History and Economy of the 428 Region
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The 428 area code was introduced as a statewide overlay for Connecticut, layered on top of every existing area code in the state to provide a fresh supply of numbers once the regional overlays approached exhaustion. Because it covers the whole state, a 428 number could belong to a hedge-fund office in Greenwich, a biotech firm in New Haven, an insurance company in Hartford, or a shoreline business near New London. Connecticut’s economy is anchored by finance and corporate headquarters in Fairfield County, the insurance industry in Hartford, aerospace and defense manufacturing statewide, Yale and the University of Connecticut, and tourism in the eastern casino region. Because 428 is brand new, it appears almost exclusively on recently activated phone lines.
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Looking Up a 428 Number
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To identify a 428 caller, use a reverse phone lookup or search the complete 10-digit number online. Because 428 is the newest code in Connecticut and can be assigned anywhere in the state, many numbers will have little or no public footprint yet, so treat unexpected 428 calls with extra caution and never share sensitive information with an unverified caller.
Nearby & Related Area Codes
Connecticut is served by five area codes. If you are researching 428, these neighboring and overlay codes are worth knowing:
- 203 – Southwestern CT / Fairfield & New Haven
- 475 – Southwestern CT overlay
- 860 – Northern & Eastern CT / Hartford
- 959 – Hartford area overlay
You can also browse our full directory of Connecticut area codes for more regional guides.
↑ See the complete list of All US Area Codes by State – every area code across all 50 states in one directory.
Explore Neighboring States
Researching area codes just across the state line? Start with these codes in the states that border Connecticut:
Frequently Asked Questions
Where is the 428 area code located?
The 428 area code is a statewide overlay covering all of Connecticut, so a 428 number can be based anywhere in the state – from Stamford and New Haven to Hartford and the eastern shore.
Why was the 428 area code created?
428 was added as a statewide overlay to provide new phone numbers across all of Connecticut once the existing regional codes and their overlays ran low on available numbers.
Do I have to dial 10 digits for 428?
Yes. As an overlay code, 428 always requires 10-digit dialing for local calls, as does every area code in Connecticut.
Is 428 a new area code?
Yes. 428 is the newest area code in Connecticut and, unlike the regional codes, it covers the entire state. It observes Eastern Time (EST/EDT).
Related 428 Guides
- Worried about spam or robocalls? Browse our Scam Alerts directory.