If you have a passport , you can travel around the world. While some countries require a visa in addition to a passport, you can travel to many places simply with a passport. A passport is a unique, electronic form of identity required to enter another country. If you have a passport, you may have noticed a number on the inside and wonder if the number is significant. Without that number, a passport may not serve its purpose.

What Makes Up a Passport

A passport may look like simply a small booklet, but it's much more than that. Not only does it hold a traveler's information, their travel history, and the visas required to visit certain countries, it's an important document in general: It provides proof of citizenship. That's why if you lose your passport or it's stolen, it's a serious issue.

As of 2007, all passports issued by the United States are electronic. They have a very small chip embedded inside the back cover, which is used as a security measure. The chip holds information that's essentially a digital clone of what's on the passport's page, including personal information, a biometric identifier, a unique chip ID number, and a digital signature that prevents the technology from being tampered with.

What a Passport Number Means

In addition to all the security information in a passport, it's the passport number that ties it directly to an individual. The passport number is essentially a code that's kept in the government's database. Find the nine numbers that comprise the passport number on the top right-hand corner of the identification page.

Before biometric encryption microchips were embedded in passports, the passport number was important for traveler identification. Customs officials use this number to match travelers with their passport and keep tabs on them.

Passport Cards

You can opt for a passport card instead of a full passport for travel to Canada, Mexico as well as to many islands in the Caribbean if you're traveling by land or sea, but not by air. While you may wonder if the passport card has the same number as a passport, it does not.

A passport number isn't as important as it once was since the necessary information is stored inside the passport chip. However, some countries still rely heavily on the number itself, so be sure to keep the number safe.