New Hampshire area codes
New Hampshire uses 1 area code. Its code 603 has been in service since 1947. It has 752 of its 786 possible number blocks allocated, 95.7% of capacity. 603 is at or past 95%, which is why new numbers there come from overlays rather than the original code. Consolidated holds 33.0% of the 752 assigned blocks across the state, ahead of Windstream at 7.7%; a further 26.1% sits with CLEC and VoIP holders outside the national carriers. In the 33 days to 30 October 2026, FTC complaints named a New Hampshire caller ID 402 times – 0.2% of all complaints in the window, most often 603 with 402 (248th of 422 nationally). NANPA records 147 rate centers in 603, and local calls take all ten digits.
The New Hampshire area code
| Code | In service | Blocks used | Largest holder | Complaints | Shares area with |
|---|---|---|---|---|---|
| 603 | 1947 | 752/786 | Consolidated 33% | 402 | no overlay |
Block share is share of allocated number blocks, not of subscribers. Complaint counts cover 28 Sep – 30 Oct 2026 and reflect spoofed caller IDs as much as real calls.
How full New Hampshire’s codes are
A code holds at most 786 blocks of 10,000 numbers each. When a code fills up, the administrator does not reclaim numbers – it adds an overlay, and from then on new numbers in the same area come from the new code.
Full or nearly full
Most room left
Who holds the number blocks
Counted from every assigned block in the state: 752 blocks, each with the holder NANPA recorded for it. Percentages are measured, not estimated.
| Holder | Blocks | Share of New Hampshire | Largest in |
|---|---|---|---|
| Consolidated | 248 | 33% | 1 code |
| Other CLEC / VoIP | 196 | 26.1% | – |
| Windstream | 58 | 7.7% | – |
| T-Mobile | 55 | 7.3% | – |
| Verizon | 45 | 6% | – |
| AT&T | 45 | 6% | – |
| Comcast | 40 | 5.3% | – |
| Lumen | 38 | 5.1% | – |
| Onvoy | 6 | 0.8% | – |
| Charter | 6 | 0.8% | – |
| Peerless | 4 | 0.5% | – |
| Telnyx | 3 | 0.4% | – |
“Other CLEC / VoIP” is not one company: it is every holder outside the national carriers counted together, which is what resellers and app-based numbers look like in the records. This is allocation, not subscribers.
Spam complaints naming New Hampshire codes
FTC Do Not Call complaints where the caller ID shown was a New Hampshire number, 28 Sep – 30 Oct 2026 (33 days). Caller IDs on spam calls are routinely faked, so these are complaints about the code, not calls proven to come from it.
Time zones
New Hampshire is in Eastern time.
Frequently asked about New Hampshire area codes
How many area codes does New Hampshire have?
1 in service. That code is 603.
What is the oldest area code in New Hampshire?
603, in service since 1947.
Is New Hampshire running out of numbers?
603 is at or past 95% of capacity, but NANPA has not opened relief planning for it, so no new code is announced.
What time zone is New Hampshire in?
Eastern time.
Which New Hampshire area code gets the most spam complaints?
603 – 402 FTC complaints in the 33 days to 30 October 2026, 248th of 422 codes nationally. Those are complaints about the caller ID shown, and spam callers routinely fake a local-looking number, so this says the code is imitated often, not that the calls come from there.
Which carrier holds the most New Hampshire numbers?
Consolidated, with 33.0% of the 752 blocks assigned across New Hampshire, ahead of Other CLEC / VoIP at 26.1%. This is allocation of blocks by the numbering administrator, not a count of subscribers – people keep their numbers when they switch carriers.
Do you have to dial 10 digits in New Hampshire?
Yes. The code is in a ten-digit dialing area, so a local call needs the area code too. Dialing seven digits reaches a recording, not a wrong number.
Sources and verification
- NANPA – NPA Database (npa_report.csv), file date 11/01/2026, retrieved Nov 1, 2026
- NANPA – CO Code Assignment Records, All States (utilized), file updated 11/01/2026, retrieved Nov 1, 2026
- FTC – Do Not Call Reported Calls Data, 28 Sep – 30 Oct 2026, retrieved Nov 1, 2026
Figures on this page are counted from those files, not copied from other sites. Spotted an error? Request a correction. How we collect and check: methodology.