What It Is
Your business appears in more places than your website: your Google Business Profile, Apple Maps, Yelp, Facebook, the chamber of commerce directory, industry sites, old press, and the data companies that feed listings to all of them. Each one carries your name, address, and phone number. NAP is the trade's shorthand for those three facts, and NAP consistency is whether they match everywhere.
How It Works
Search engines compare what those sources say about you. When they agree, the facts reinforce each other. When they do not, the listings pull against each other: an old address from before a move, a tracking number that was never retired, a name written three different ways. Google's guidelines ask businesses to represent themselves the way they are known in the real world, and consistently.
Mismatches are rarely anyone's fault. They pile up over years, from moves, rebrands, a new phone system, or a directory that copied an old listing and never updated it. Finding them means searching for the business in each place and listing every variant, then correcting them at the source, starting with the ones that feed the others.
Why It Matters for Being Found
Customers read consistency as a sign of trust, and so does Google. A customer who calls a disconnected number or drives to an old address does not try again; they call the next business. The same mismatch that loses that customer also makes it harder for Google to be confident about which details are right. For AI the effect is sharper still, because an AI answer gives one address, not a list, and it will give whichever one it found.