Postage for Large Envelopes & Flats

Looking to mail a large envelope? Here, you'll find up-to-date rates for mailing flats via the USPS as well as information on letter dimensions, requirements, and more.

USPS Priority Mail - Free Boxes, Sizes and Flat Rate

Priority Mail Flat Rate Padded Envelope 12 1/2 x 9 1/2 – Stamps.com Supplies Store

Priority Mail Express Flat Rate Envelope 12 1/2 x 9 1/2, 10/pack – ONYX Products®

How To Ship Flats With Stamps.com - Stamps.com Blog

Postage for Large Envelopes & Flats

USPS Shipping Template, Mail Measure, Mail Sizer, Slot Template, Letter Envelope Size Guide, Measuring tool for USPS letter flat large envelope : Office Products

Know What You're Mailing: Letters vs. Flats vs. Parcels

First Class Flats - University Mail Services

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January 24, 2021 USPS Rate Increase: See How It Will Impact Your Budget

Postage for Large Envelopes & Flats

Priority Mail boxes and envelopes are shrinking