Area code 551: New Jersey
Area code 551 is a US state area code for New Jersey, on Eastern Time. It has 294 prefixes in service across 22 rate centers, the largest being Jersey City, Hackensack and Bayonne. It shares its area with 201, so local numbers there can start with any of them. Local calls there take 10 digits.
Local time in area code 551
America/New_York
Prefixes in service
294 of 792 possible
22 rate centers
Area code 551 facts
| Location | New Jersey, United States |
|---|---|
| Time zone | Eastern Time |
| Overlays | 201 |
| Overlay of | 201 |
| In service since | December 29, 2001 |
| Local calls | 10 digits |
| Carrier | Not shown. An area code is where a number was issued; numbers port between carriers. Check line type |
Which cities and towns use area code 551?
NANPA records each prefix against a rate center, the local billing area a number belongs to, usually named after its main town. These are the 551 rate centers with the most prefixes in service. 10 smaller ones aren't listed.
| Rate center | Prefixes |
|---|---|
| Jersey City | 53 |
| Hackensack | 44 |
| Bayonne | 31 |
| Union City | 23 |
| Ramsey | 20 |
| Fair Lawn | 17 |
| Cliffside | 14 |
| Kearny | 11 |
| Ridgewood | 10 |
| Rutherford | 8 |
| Closter | 8 |
| Wyckoff | 6 |
Source: NANPA central office code assignments, file dated 10/17/2026. Each prefix holds up to 10,000 numbers.
How do I dial a 551 number?
NANPA's dialling plan for 551: local calls inside the code take 10 digits, toll calls 10 digits. From another area code, dial 1 first. From abroad, use +1. The examples use 555-0147, from a range reserved for fictional numbers.
| Local call inside 551 | 551-555-0147 |
|---|---|
| From another US or Canadian area code | 1-551-555-0147 |
| From outside North America | +1 551 555 0147 |
| E.164, for CRMs and SMS tools | +15515550147 |
When did area code 551 start?
Area code 551 went into service on December 29, 2001 as an overlay of 201. Today 551 and 201 cover the same area as an overlay, which is why 10-digit dialling is needed for local calls there.
Tools for 551 numbers
- Area code lookup
Look up any code or a whole list of numbers, or find the codes for a state or city.
- Area code time zone
Local time for a list of numbers, with a callable-now flag.
- NPA-NXX lookup
Rate center and state for one prefix, a level below the area code.
- TCPA calling hours checker
Whether it's inside the federal 8 a.m. to 9 p.m. calling window there now.
Next step
A 551 number tells you where it was issued, not what it is now.
Mobiles, landlines and VoIP lines share area codes, and numbers move between carriers. A live line-type and carrier lookup on every number in your list says which is which, and that decides which calling and texting rules apply. It's in the Email + Phone plan.
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Area code 551 questions
- What state is area code 551?
- Area code 551 is in New Jersey, United States. Its largest rate centers by number of prefixes are Jersey City, Hackensack, Bayonne, Union City and Ramsey.
- What time zone is area code 551 in?
- Eastern Time.
- What area codes overlay 551?
- 201. An overlay adds a new code to the same area instead of splitting it, so neighbours can have different area codes and local calls need 10 digits.
- When did area code 551 start?
- Area code 551 went into service on December 29, 2001 as an overlay of 201.
- Is a 551 number a cell phone or a landline?
- The area code can't tell you. In the US and Canada mobiles, landlines and VoIP lines share area codes and prefixes, and numbers move between carriers and line types. Only a live line-type lookup answers it for one number.
- How many phone numbers does area code 551 have?
- 294 of its 792 possible prefixes are in service, and each prefix holds up to 10,000 numbers. That counts prefixes assigned to carriers, not numbers in use.
Other area codes in New Jersey
Sources
Location, overlays, in-service date and dialling plan: NANPA NPA database, file dated 10/16/2026. Prefixes and rate centers: NANPA central office code assignments, 10/17/2026. Time zones mapped to the IANA time zone database. By the SimpleVerifier Team; how we build these pages.