Area codes in Boston, Massachusetts
Boston, Massachusetts uses 2 area codes — 617 and 857. The main Boston area code is 617.
Area codes serving Boston
Phone numbers in Boston are written as ten digits — for example (617) 555-0190 — and fall in the Eastern Time zone.
How Boston came to have 2 area codes
The original Boston area code is 617, in service since 1947. As the area ran low on available numbers, an overlay code was added over the same region for new phone lines: 857 (2001). Existing numbers kept their original code — an overlay never forces anyone to change their number — which is why Boston now uses all 2 codes and every local call is dialed with ten digits.
All Massachusetts area codes · Is a Boston call a scam?
Nearby cities
- Cambridge area codes
- Winchester area codes
- Quincy area codes
- Lexington area codes
- Brockton area codes
- Lowell area codes
- Worcester area codes
- Providence area codes
Frequently asked questions
What is the area code for Boston?
The main area code for Boston, Massachusetts is 617. Boston is now served by 2 area codes in total: 617, 857.
How many area codes does Boston have?
Boston has 2 area codes: 617, 857.
Why does Boston have more than one area code?
As Boston used up the numbers available in its original area code (617, in service since 1947), additional "overlay" codes were added over the same area so new phone numbers could keep being assigned.
How do you dial a Boston number?
Dial all 10 digits — the area code (617 or 857) followed by the 7-digit local number. From abroad, dial +1, then the area code and number.
Sourced from the official NANPA (North American Numbering Plan Administrator) numbering database, current as of August 2, 2026. Refreshed monthly.