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Flat Rate — Quick Reference
   
 

Available for Domestic and International

PRIORITY MAIL EXPRESS
Flat Rate Envelope
12-1/2" x 9-1/2"

Legal Flat Rate Envelope
15" x 9-1/2"

Padded Flat Rate Envelope
12-1/2" x 9-1/2"

Flat Rate Boxes
Top Loading
11" x 8-1/2" x 5-1/2" – Inside
11-1/4" x 8-3/4" x 6" – Outside

Side-Loading
13-5/8" x 11-7/8" x 3-3/8" – Inside
14" x 12" x 3-1/2" – Outside

PRIORITY MAIL
Flat Rate Envelope
12-1/2" x 9-1/2"

Legal Flat Rate Envelope
15" x 9-1/2"

Padded Flat Rate Envelope
12-1/2" x 9-1/2"

Gift Card Flat Rate Envelope
10" x 7"

Small Flat Rate Envelope
10" x 6"

Window Flat Rate Envelope
10" x 5"

Small Flat Rate Box
8-5/8" x 5-3/8" x 1-5/8" – Inside
8-11/16" x 5-7/16" x 1-3/4" – Outside

Medium Flat Rate Boxes
Top Loading
11" x 8-1/2" x 5-1/2" – Inside
11-1/4" x 8-3/4" x 6" – Outside

Side Loading
13-5/8" x 11-7/8" x 3-3/8" – Inside
14" x 12" x 3-1/2" – Outside

Large Flat Rate Box
12" x 12" x 5-1/2" – Inside
12-1/4" x 12-1/4" x 6" – Outside

APO/FPO/DPO
Large Flat Rate Box
12" x 12" x 5-1/2" – Inside
12-1/4" x 12-1/4" x 6" – Outside

Board Game Large Flat Rate Box
23-11/16" x 11-3/4" x 3" – Inside
24-1/16" x 11-7/8" x 3-1/8" – Outside

Large Video Box (Flat Rate pricing for international only)
9-1/4" x 6-1/4" x 2" – Inside
9-9/16" x 6-7/16" x 2-3/16" – Outside

DVD Box (Flat Rate pricing for international only)
7-9/16" x 5-7/16" x 5/8" – Inside
8-3/4" x 5-9/16" x 7/8" – Outside

Note: Flat Rate prices are available when material is sent in a USPS-produced Flat Rate Envelope or Box. When sealing a Flat Rate Box or Flat Rate Envelope, the container flaps must be able to close within the normal folds. Tape may be applied to the flaps and seams to reinforce the container; provided the design of the container is not enlarged by opening the sides and the container is not reconstructed in any way.

Weight restrictions for domestic Priority Mail Express and Priority Mail Flat Rate Envelopes and Boxes are 70 pounds.

Weight restrictions for international Flat Rate Envelopes and Small Flat Rate priced boxes are 4 pounds and 20 pounds for the Medium and Large Flat Rate Boxes.

You may order free packaging supplies at usps.com/store.