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Postal Encyclopedia

Letter

Updated 2026-07-24

Letter-size mail

Preparation & Production

A machinable letter generally falls between 3.5 x 5 inches and 6.125 x 11.5 inches and within thickness/weight limits.

Definition reviewed 2026-07-24. Plavidian reference, written from the USPS Domestic Mail Manual. Final mail classification, postage, and preparation are confirmed after list processing and production review.

Related terms in Preparation & Production

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