Area codes in Cambridge, Massachusetts
Cambridge, Massachusetts uses 2 area codes — 617 and 857. The main Cambridge area code is 617.
Area codes serving Cambridge
Phone numbers in Cambridge are written as ten digits — for example (617) 555-0190 — and fall in the Eastern Time zone.
How Cambridge came to have 2 area codes
The original Cambridge 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 Cambridge now uses all 2 codes and every local call is dialed with ten digits.
All Massachusetts area codes · Is a Cambridge call a scam?
Nearby cities
- Boston area codes
- Winchester area codes
- Lexington area codes
- Quincy area codes
- Brockton area codes
- Lowell area codes
- Worcester area codes
- Providence area codes
Frequently asked questions
What is the area code for Cambridge?
The main area code for Cambridge, Massachusetts is 617. Cambridge is now served by 2 area codes in total: 617, 857.
How many area codes does Cambridge have?
Cambridge has 2 area codes: 617, 857.
Why does Cambridge have more than one area code?
As Cambridge 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 Cambridge 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.