Area code 603

About area code 603

Area code 603 is a geographic area code in New Hampshire, in service since January 1, 1947, according to the North American Numbering Plan Administrator (NANPA). It is not part of an overlay, so every number in its territory starts with 603. It is in the Eastern time zone. The places with the most assigned exchanges include Manchester, Nashua, Concord, Derry, and Dover.

Cities and towns in area code 603

603 holds 100% of the 752 central office codes assigned in New Hampshire, the most of any code in the state. 119 Census places could be matched to rate centers with 603 exchanges; the most populous are Manchester (116,000), Nashua (91,851), Concord (44,674), and Derry (34,062). Each place page lists the exact prefixes and carriers for that town.

How calls are dialed in 603

According to NANPA's dialing-plan data, local calls within 603 are dialed as ten digits (area code plus number) and toll calls as ten digits (area code plus number). Because local calls need the area code, business cards, signage and website copy should always show the full ten-digit number. NANPA's dialing-plan note for this code reads: "1+10 digit permissible at service provider discretion."

Carriers with 603 numbers

49 carriers hold the 752 central office codes assigned in 603. Consolidated Comm of No. New England-nh has the most, with 246 (33%). 602 of the codes (80%) 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.

Local calling areas in 603

NANPA assigns each central office code to a rate center, the local calling area that decides whether a call is local or toll. 603 has codes in 147 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.

Number supply in 603

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). 752 are assigned in 603, 94% of 800. 34 were assigned in 2020 or later.

Getting a 603 number for your business

Callata is a business phone system priced at $99 a month with 5 users included, then $20 per additional user. Callata Office includes up to 3 local business numbers, unlimited inbound calling, 1,500 pooled outbound US and Canada minutes per user each month, a browser softphone that can also ring your cell, voicemail with transcription, call recording with AI summaries, business-hours routing and E911 on every number.

Porting a number you already use in area code 603 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.