Area codes / Massachusetts / 857
The 857 area code
857 is an area code in Massachusetts, in the Eastern time zone. Get a local 857 number for your business, shared by everyone who answers it, or bring the 857 number you already have.
857 at a glance
- State
- Massachusetts
- Time zone
- Eastern
- In service since
- 2001
- Overlay
- Shares its area with 617
- Local calls
- Dialed with all ten digits (area code and number)
Get a 857 business number
When you sign up for Onyx Phone, you pick a local number by area code: search 857, narrow it by the next three digits or the last four if you want something memorable, and it's yours on the spot. Which numbers are free changes daily. If you don't find one you like, 617 covers the same area.
The number rings everyone you assign to it, in the browser, on the iPhone and Android apps, and on desk phones, and texts from it are unlimited once US carriers approve your business. Your plan includes one number for each user, and more numbers are $5 a month.
Calling 857 customers
Local calls in 857 are dialed with all ten digits: the area code, then the number. Callers are on Eastern time, so set your business hours to match if most of your customers are here.
Calls from Onyx Phone show your business number, and once your business is verified, your caller ID name too, so 857 customers see who's calling.
Questions about area code 857
What state is area code 857?
Area code 857 is in Massachusetts.
What time zone is area code 857 in?
Area code 857 is in the Eastern time zone.
Is 857 an overlay area code?
Yes. 857 shares its area with 617. Numbers in either code ring the same region, and local calls there are dialed with all ten digits.
Can I get a 857 business number?
Onyx Phone sells US local numbers. When you pick your number, search the 857 area code; which numbers are free changes daily. If none are free, 617 covers the same area.
Can I keep the 857 number I already have?
Yes. Moving a number to Onyx Phone is free on every plan and usually takes 3 to 7 business days. You answer on a temporary number until it moves.
Included on every plan
Starter is $17, Business is $29, Scale is $42 per user a month, or less billed yearly. The plan includes a business number for each user and unlimited calling and texting in the US and Canada. Every plan starts with a 7-day free trial, and moving your current number over is free.
Area code data from the North American Numbering Plan Administrator (NANPA), file of October 24, 2026.