us postal service letter size

us postal service letter size refers to the dimensions of a letter that can be sent via USPS’s standard letter mail service. The typical size for a letter is 4-1/8″ x 9-1/2″ to 6-1/8″ x 11-1/2″. Anything within this size range is eligible for First-Class Mail, which is the USPS’s most economical service for sending personal or business correspondence. If a letter exceeds these dimensions, it may require a different mailing class or additional postage.