USPS postcard rules we check

Piece size matches selection

Artwork dimensions must match the selected trim size (bleed of up to 0.125" per side allowed).

DMM 201.1 Physical Standards — Letter-size dimensions · DMM 2026-07

Aspect ratio 1.3 to 2.5

Length divided by height must be between 1.3 and 2.5 or the piece is nonmachinable.

DMM 201.2.1 Nonmachinable Criteria — Letters · DMM 2026-07

Size qualifies for mail class

First-Class postcard rate needs a piece no larger than 4.25" x 6". EDDM Retail needs a flat-size piece (taller than 6.125" or longer than 11.5").

DMM 201.1.1 Postcard dimensions; EDDM Retail (DMM 140) · DMM 2026-07

Barcode clear zone is empty

The bottom 5/8" across the rightmost 4-3/4" of the address side must be free of any printing.

DMM 202.5 Barcode Placement — Letters (barcode clear zone) · DMM 2026-07

Address block inside OCR read area

The delivery address must sit within the OCR read area: 1/2" from left and right edges, between 5/8" and 2-3/4" from the bottom edge.

DMM 202.2 OCR Read Area · DMM 2026-07

Postage area in upper right

The indicia (permit imprint) or stamp area must be in the upper right corner of the address side.

DMM 604.5 Permit Imprint (Indicia); DMM 602.1 Address Placement · DMM 2026-07

EDDM indicia and "Postal Customer" line

EDDM pieces need the EDDM Retail indicia and the "Local Postal Customer" (or ECRWSS) address line.

EDDM Retail requirements (DMM 140, 604.5) · DMM 2026-07

Critical content inside safe margin

Text and logos should stay at least 1/8" inside the trim edge so cutting tolerance does not clip them.

Print best practice (not a USPS rule) — referenced for production safety · DMM 2026-07

No text or art in reserved zones

AI check for text, logos, or images printed in the barcode clear zone.

DMM 202.5 Barcode Placement — Letters · DMM 2026-07