A Priority Mail Flat Rate Envelope is one of the United States Postal Service's Flat Rate packages which always ships for the same rate within the USA as long as your order fits inside the packaging. The flat rate envelope is intended for documents; if you want to ship something that isn't a document with USPS Flat Rate service, a Small Flat Rate Box may be more suitable.
Where to Find a Flat Rate Envelope
Flat Rate envelopes can be found at your local post office or ordered free online at USPS.com.
Dimensions of Flat Rate Envelopes
- 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"
Rates for Flat Rate Envelopes
The cost to ship a flat rate envelope varies by:
- Rate tier - Retail, Commercial
- Service - Priority Mail, Priority Mail Express
- Destination - domestic, international
- Envelope type - standard, legal, padded envelope
Restrictions for Flat Rate Envelopes
Flat Rate Envelopes are perfect for sending documents.
If you need to send items other than documents, make sure that the items do not expand the envelope in any way. When sealing a Flat Rate Envelope, the container flaps must be able to close within the normal folds.
Also, shipments must weigh less than 70 lbs.
More questions? Check out USPS' DMM Regulations for Flat Rate Envelopes.