Social Security number

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

July 23, 2026

Quick Summary

A Social Security number (SSN) is a unique nine-digit number assigned by the U.S. government to each citizen. It is primarily used for the Social Security program and for various official forms and records. The abbreviation "SSN" is commonly used to refer to a Social Security number.12

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

2 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

cybercrime
Identity theft and invasion of privacy
…official identity card but a Social Security number that has long served as a de facto identification number. Taxes are collected on the basis of each citizen’s Social Security number, and many private institutions use the number to keep track of their employees, students, and patients. Access to an individual’s…
Read More
…official identity card but a Social Security number that has long served as a de facto identification number. Taxes are collected on the basis of each citizen’s Social Security number, and many private institutions use the number to keep track of their employees, students, and patients. Access to an individual’s…
Read More