Tags may be used in decisions by an access management service regarding access of computing resources (“resources”) by principals (e.g., users, roles, etc.). The tags may also be used to determine cost information, for grouping resources and/or principals, and for other reasons. The tags may be assigned to principals, to resources, or both. The resource may be a virtual or physical type of computing resource. Tags may be metadata, which may include a key-value pair. Tags may include email addresses, cost centers, project identifiers, location, team name, etc. The value may be a number, letters, or a combination of both. In some embodiments, the values may be limited to certain numbers or bytes, and some numbers and/or letter combinations may be excluded for special use.