NANP number decoder

Break a North American number into its parts — each explained, and for real area codes backed by live data from NumberResearch.

Privacy by design: the number you type never leaves your browser. Decoding happens locally; only the 3-digit area code is used to fetch public data. This is a structural decoder — it does not identify who owns or is calling from a number.

This decoder runs in your browser and needs JavaScript enabled. With it off, see the NPA, NXX and thousands-block definitions directly.

What the parts mean

A number is country code + area code (NPA) + prefix (NXX) + a four-digit line number. The first digit of the four-digit line number — the seventh digit of the 10-digit national number, not counting the country code +1 — marks which pooled thousands-block of 1,000 numbers it belongs to.