PrefixBook began with an evening of hurt feelings over a phone number. A relative of our editor had saved a contact with a doubled country code, kept getting a recording, and decided the person on the other end had blocked her. Nobody had blocked anybody. One digit too many had sat in the contact for years. This page tells how that evening turned into a small reference site, what the site is, and what it refuses to be.
How it started
The editor, Marit Holloway, kept a paper list of dialing mishaps that friends and family sent her. The same few entries repeated: a stray 1, a leading zero that should have been dropped, a Caribbean code mistaken for a neighbour's. Answering each one by text message got old, and a short, boring explanation is exactly what a reference book is for. In mid-September 2026 the first guide went up, on why every US number starts with +1. Others followed as the list suggested them, and the latest are dated in early October 2026.
Most phone confusion starts before the number begins.
What it is now
PrefixBook is an independent information site about phone number prefixes in North America: country calling codes, area codes, dialing habits and the prefixes that change what a call costs. It has two parts. The first is the prefix reader, a small tool that takes a US or Canadian style number and reports what its digits say: the international form, the area code, the country or kind of service, and for geographic US codes the main places and the time zone. The second is a shelf of guides, each in the shape that suits its subject, from why numbers start with +1 to a glossary of international dialing.
We have no affiliation with any phone carrier, any government agency or any people-search company, and nothing here is sponsored by one. Names of carriers and agencies appear only as sources or to explain a label you may see on your screen.
What we kept out
The reader does not identify the owner of a number. It does not tell you the carrier, the line type or whether other people have complained about the number. We keep no call histories and no reputation scores. Spam labels from carriers and apps are guesses made from patterns, and we say so whenever we mention them. If a site tells you it can name any caller for free, read the small print before you type a number into it. We also publish no testimonials, no ratings and no statistics we cannot trace.
How a page gets checked
Each guide is written from primary sources: the North American Numbering Plan Administration for area codes and numbering rules, the FTC and FCC for consumer rules and complaint channels, the Do Not Call Registry for its own procedures, and Apple and Google support pages for menu paths on phones. Where a page leans on an outside rule, it links to the source in the text. A visible "Updated" date shows when it was last read through against them. Where we are unsure of a detail, such as a price or a carrier feature that changes often, we say it depends and send you to the carrier.
If we got something wrong
Mistakes happen, especially in a subject where carriers and rules change. If you spot one, write to [email protected] or use the contact page. Tell us which page and what you think is wrong, and ideally where the right answer lives. We check the claim against its source, fix the page if you are right and update the date. Corrections go to the front of the queue. There is no team of experts behind a curtain, only one editor, and we would prefer you knew that.
What happens to your visit
You do not need an account. The site sets no cookies and runs no analytics, advertising or third-party scripts and fonts. Numbers typed into the reader are handled on the server for that request only and are not saved in a database, though the web server's standard logs hold requests for about a week. The privacy policy describes this fully, and the terms and disclaimer set out the limits of what we offer.