If your business validates or sends messages to U.S. or Canadian numbers, you’re already working within the North American Numbering Plan — even if you’ve never heard of it.
The NANP is the foundation of all U.S. and Canadian phone number formats. It’s how numbers are assigned, structured, and understood by carriers and validation systems alike.
In this article, we’ll break down what the NANP is, why it matters for modern messaging, and how to work with it in your validation and communication flows.
🧭 What Is the NANP?
The North American Numbering Plan (NANP) is a telephone numbering system that covers:
United States
Canada
Most U.S. territories (e.g. Puerto Rico, Guam)
Several Caribbean nations
It was created in the 1940s to standardize phone numbering across regions. Today, it defines how phone numbers are formatted and routed across this entire zone.
📞 NANP Number Structure
Every NANP number is 10 digits long and follows this structure:
(NPA) NXX-XXXX
Where:
NPA – Numbering Plan Area (aka Area Code)
NXX – Central Office Code
XXXX – Subscriber Number
Example:
(818) 555-1234
818 = Area code (Los Angeles)
555 = Exchange
1234 = Individual line
Note: All numbers are prefixed with +1 when used internationally (e.g. +1-818-555-1234).
🧠 Why the NANP Matters for Phone Validation
Most U.S. and Canadian numbers look valid — but that doesn’t mean they actually work. Here’s why:
Area codes can be reused in different states or regions
Some prefixes (like 555) are reserved or not routable
Numbers can be ported, deactivated, or reassigned
Not all 10-digit numbers are SMS-capable
A phone number might fit the NANP structure and still be unreachable, disconnected, or even fraudulent.
🧪 How CheckThatPhone Validates NANP Numbers
CheckThatPhone doesn’t just rely on area codes or syntax. It validates NANP numbers using real-time telecom data, checking:
Whether the number is active and routable
The line type (mobile, VoIP, landline)
Portability and carrier info
Deliverability and current status
Geo/timezone data inferred from area code or IP (if provided)
This means you can:
Confirm if a number is real and reachable
Detect if it’s been suspended or deactivated
Decide whether to send a message, call, or flag it for review
📦 Use Cases in B2B Messaging
Sales and lead scoring – Filter out unreachable numbers
SMS campaign prep – Clean your list for NANP-only targeting
Customer support – Route calls to valid mobile numbers
Fraud prevention – Flag mismatched or out-of-region numbers
Signup flows – Instantly validate number format and status
✅ Final Thoughts
The NANP may be old-school infrastructure, but it’s still the backbone of North American phone communication. Knowing how it works — and how to validate numbers within it — helps your business improve accuracy, reduce failures, and stay compliant.
CheckThatPhone makes it easy to work with NANP numbers the right way, using real-time carrier data for validation and delivery success.