Mail Express Size Price
Flat Rate Envelope 12-1/2" x 9-1/2" $25.50
Legal Flat Rate Envelope 15" x 9-1/2" 25.70
Padded Flat Rate Envelope 12-1/2" x 9-1/2" 26.20
Priority Mail Size Price
Flat Rate Envelope 12-1/2" x 9-1/2" or smaller $7.35
Legal Flat Rate Envelope 15" x 9-1/2" $7.65
Padded Flat Rate Envelope 12-1/2" x 9-1/2" $8.00
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. $7.90
Medium Flat Rate Boxes 11" x 8-1/2" x 5-1/2" Inside
11-1/4" x 8-3/4" x 6" Outside
13-5/8" x 11-7/8" x 3-3/8" Inside
14" x 12" x 3-1/2" Outside $14.35
Large Flat Rate Boxes 12" x 12" x 5-1/2" Inside
12-1/4" x 12-1/4" x 6" Outside
23-11/16" x 11-3/4" x 3" Inside
24-1/16" x 11-7/8" x 3-1/8" Outside $19.95
APO/FPO/DPO Flat Rate Box 12" x 12" x 5-1/2" Inside
12-1/4" x 12-1/4" x 6" Outside $18.45
1. Packaging only available at USPS.com.