Phone Number Format Guides

Phone numbers look different depending on whether you're storing them in a database, displaying them to a customer, embedding them in a web page, or sending them to an SMS gateway. Each use case has a standard — E.164 for APIs, international format for human-readable display, national format for local audiences, and RFC3966 for clickable tel: links. The guides below walk through the rules, examples, and common mistakes for each standard and each country.

Format Standards

The four internationally recognised ways to write a phone number — pick the one that matches your use case.

Country Guides

Country-specific rules for number length, trunk prefix, mobile prefixes, and how to dial internationally — complete with E.164 examples and a free formatter.