USPS Mail Classes

The USPS has a variety of Mail Classes you can choose from for all your shipping and mailing needs. Select from the sections below for details about each available service class.

Ground Advantage™

In July 2023, USPS replaced USPS Retail Ground®, First-Class Package®, and Parcel Select Ground® services with the new Ground Advantage™ service. USPS Ground Advantage is a reliable way to ship packages up to 70 lbs in 2-5 business days. USPS Ground Advantage is a solution for shippers who need affordable, domestic shipping to all 50 states, U.S. military bases, territories, possessions, and Freely Associated States.

  • 2 - 5 business day delivery time

  • Ship packages up to 70 lbs.

  • Maximum dimensions: 18" width, 22" length, 15" height

  • Best-priced service for items up to 15.99 oz, based on weight and zone (distance)

  • Weights are rounded up to 4 oz, 8 oz, 12 oz, and 15.99 oz.

  • Packages greater than 15.999 oz are charged by the pound, up to 70 lbs (rounded up)

  • Includes tracking

  • Includes $100 loss/damage coverage

Stamps.com will automatically issue a Ground Advantage label when you select First Class as your service and Package as your package type.

First Class Mail

First-Class Mail is the most popular and economical way to send standard postcards, letters, and large envelopes up to 15.99 oz. Most letters or packages take 2 to 3 days to arrive at their final destination in the U.S.

When mailing postcards, you must use NetStamps. For domestic letters, you can print NetStamps or print postage directly on the envelope. For Large Envelopes/Flats, you can print NetStamps or create a shipping label.

Mail Item

Width

Length

Weight

Postcard

4.5" max

6.00" max

Up to 1 oz.

Letter

6.125" max

11.5" max

Up to 3.50 oz

Large Envelope/Flat

12.00" max

15.00" max

Up to 13.00 oz

First-Class Mail International

First-Class Mail International is an affordable way to send letters, postcards, and large envelopes/flats to international destinations. Delivery generally takes 7 to 21 days, depending on the destination. First-Class Mail International has a weight limit of 15.994 ounces when sending documents.

When mailing international postcards or letters, you must use NetStamps.

The USPS considers the following to be documents:

  • Audit and business records

  • Personal correspondence

  • Circulars

  • Pamphlets

  • Advertisements

  • Written instruments not intended to be resold

  • Money orders, checks, and similar items that cannot be negotiated or converted into cash without forgery

First-Class Mail International for Large Envelopes & Flats containing merchandise is no longer offered directly from the USPS. However, Stamps.com continues to offer this service for items weighing up to 4 lbs, with a value of up to $400.00.

When you select First-Class Mail International Large Envelope/Flat, you will receive a Global Advantage Program label with both our postal processing facility address and your international recipient's address. At the processing facility, all needed customs forms are applied, and your parcel is fast-tracked to its destination.

Best of all, this service is up to 65% less than First-Class Package International.

First-Class Package Service International

First-Class Package International Service is the most affordable way to send small packages internationally directly with USPS.

Electronic USPS Delivery Confirmation is included.

  • Maximum Size: Length + Height + Width cannot exceed 136"

  • Maximum Weight: Up to 64oz.

  • Maximum value: $400

Priority Mail

Priority Mail is the fast yet economical way to send medium-sized envelopes and packages up to 70 pounds within the United States. Delivery times are 1 to 3 days. The USPS offers free Priority Mail boxes and envelopes. When you use your own packaging, USPS determines rates by weight, distance, and package dimensions.

  • Maximum Size: Length + 2 x Width + 2 x Height cannot exceed 108"

  • Weight: up to 70lbs

Priority Mail Flat Rate

Priority Mail Flat Rate envelopes and boxes offer 1 to 3-day delivery, a flat rate for up to 70lbs., and eliminates the need to weigh packages or calculate shipping fees. If it fits (with the box closing securely and with no bulges), it ships.

To order free USPS Flat Rate Boxes or any other free Priority Mail or Priority Mail Express supplies go to the Stamps.com Store.

To print postage for flat rate boxes, use the Packages window to print out shipping labels. You can print addresses, postage, and tracking information in one step and save up to 11% on Priority Mail and 3% on Priority Mail Express.

Mail Item

Width

Length

Height

Weight

Flat Rate Envelope

9.5"

12.5"

Up to 70 lbs.

Legal Flat Rate Envelope

9.5"

12.5"

Up to 70 lbs.

Padded Flat Rate Envelope

9.5"

15"

Up to 70 lbs.

Small Flat Rate Box

8 11/16"

5 7/16"

1.75"

Up to 70 lbs.

Medium Flat Rate Box top load

11.25"

8.75"

6"

Up to 70 lbs.

Medium Flat Rate Box Side Load

14"

12"

3.5"

Up to 70 lbs.

Flat Rate Box* top load

12.75"

12.75"

6"

Up to 70 lbs.

Large Flat Rate Box* side load

24 1/16"

11 7/8"

3 1/8"

Up to 70 lbs.

*Can also be used to ship to APO/FPO addresses, military posts, or US Navy ships across the world.

Priority Mail International

USPS Priority Mail International is an expedited way to send mail and packages weighing up to 70* pounds to destinations around the world. Priority Mail International delivery is usually within 6-10 days.

To order free USPS Flat Rate Boxes or any other free Priority Mail or Priority Mail Express supplies go to the Stamps.com Store.

  • Maximum Size: Length + 2 x Width + 2 x Height cannot exceed 108"

  • Weight: Up to 70 lbs

*Maximum weight and size will vary by country.

Priority Mail International Flat Rate

USPS Priority Mail International Flat Rate boxes and envelopes are cost-effective for envelopes weighing less than 4 lbs and boxes weighing less than 20 lbs. Priority Mail International delivery is usually within 6-10 days.

To order free USPS Flat Rate Boxes or any other free Priority Mail or Priority Mail Express supplies go to the Stamps.com Store.

Mail Item

Width

Length

Height

Weight

Int'l Flat Rate Envelope

9.5"

12.5"

4lb. max

Int'l Padded Flat Rate Envelope

9.5"

12.5"

4lb. max

Int'l Legal Flat Rate Envelope

9.5"

15"

4lb. max

Int'l Small Flat Rate box

8 11/16"

5 7/16"

1.75"

4lb. max

Int'l Medium Flat Rate box top load

11.25"

8.75"

6"

20lb. max

Int'l Medium Flat Rate box side load

14"

12"

3.5"

20lb. max

Int'l Large Flat Rate box top load

12.75"

12.75"

6"

20lb. max

Int'l Large Flat Rate box side load

24 1/16"

117/8"

3 1/8"

20lb. max

Priority Mail Express

USPS Priority Mail Express is the fastest service offered by USPS, and it includes up to $200 loss/damage coverage. Guaranteed delivery in 1 to 2 days, on any day of the year, including Sundays and holidays.

  • Maximum Size: Length + 2 x Width + 2 x Height cannot exceed 108"

  • Weight: Up to 70 lbs.

The best option for printing postage for Priority Mail Express is to use shipping labels.

Priority Mail Express Packaging Requirements

All items must be in Priority Mail Express packaging, bear Priority Mail Express stickers or tape, or otherwise be distinctively marked Priority Mail Express.

Priority Mail Express International

USPS Priority Mail Express International is the fastest USPS International Service with delivery to over 190 countries. Certain countries include 3-5 business day guaranteed service (see list for guaranteed countries). The service includes free pickup and $200 loss/damage coverage up to 70 lbs.

If a package is not delivered by the guaranteed date, USPS will refund shipping costs.

  • Maximum Size: Length + 2 x Width + 2 x Height cannot exceed 108"

  • Weight: Up to 70 lbs.

Priority Mail Express Flat Rate Envelopes

Priority Mail Express Flat Rate Envelopes offer fast, overnight shipping to all U.S. addresses, including PO Boxes and Military Mail. The service also includes up to $100 in loss/damage coverage.

Mail Item

Width

Length

Height

Weight

Flat Rate Envelope

9.5"

12.5"

70lb. max

Express Padded Flat Rate Envelope

9.5"

12.5"

70lb. max

Express Legal Flat Rate Envelope

9.5"

15"

70lb. max

Priority Mail Express International Flat Rate Envelopes

USPS Priority Mail Express International is the fastest USPS International Service with delivery to over 190 countries. Certain countries include 3-5 business day guaranteed service (see list for guaranteed countries). The service includes free pickup and $200 loss/damage coverage up to 70 lbs.

If a package is not delivered by the guaranteed date, USPS will refund shipping costs.

Mail Item

Width

Length

Weight

Int'l Flat Rate Envelope

9.5"

12.5

70lb. max

Int'l Padded Flat Rate Envelope

9.5"

15"

70lb. max

Int'l Legal Flat Rate Envelope

9.5"

15"

70lb. max

Priority Mail Express Delivery Options & Special Services

There are several delivery options and special services available for Priority Mail Express:

  • Signature Required: Select this free option if you want the USPS to only deliver the item when someone signs for it.

  • Do not deliver on Saturday: Select this free option when your item is scheduled to be delivered on a Saturday but you want it held until the following Monday. This is a great option to use when shipping valuable items to a business address.

  • 10:30 AM Delivery: Select this service when you would like your package to be delivered before 10:30 AM on its delivery day. Please note that this option is not available for all destination ZIP codes or mailing days.

  • Sunday/Holiday Delivery Guaranteed: Select this service when you would like your package to be delivered even on Sundays and Holidays. When selecting this delivery option, please note the following:

    • This service is only available when the mailing date of your package is a Friday or Saturday.

    • This service is not available for all destination zip codes. See a list of destination ZIP codes eligible for this service.

    • This service is not a money-back guarantee for Sunday delivery.

  • Collect on Delivery: USPS will collect payment for postage and merchandise for you.

  • Return Receipt: Get a postcard signed by the person who accepted your package. Electronic Return Receipt is not available for this service.

USPS Priority Mail Express Rates and Restrictions

When you use Priority Mail Express, you have two packaging options:

  • USPS Flat-Rate Envelopes: These free USPS envelopes allow you to send any item, up to 70 pounds, that will fit comfortably inside for one low rate.

  • Your Packaging: When you use your own thick envelope or box you will be charged postage based on weight and distance.

If using your own packaging, keep the following in mind:

  • The distance of the longest side plus twice the width plus twice the height can be no more than 108".

  • Weighs no more than 70 pounds.

  • All items must be in Priority Mail Express packaging, bear Priority Mail Express stickers or tape, or otherwise be distinctively marked "Priority Mail Express" (if you are using shipping labels, the label will clearly identify the mailpiece as Priority Mail Express).

  • Sunday and Holiday delivery are available for an extra charge.

  • Next-day shipments going to or originating from Alaska or Hawaii are not eligible for Priority Mail Express.

  • Next-day delivery will arrive between 12 noon and 3 p.m., depending on your location.

  • To qualify for Next-day delivery, you must present your mailpiece to your local Post Office by a time determined by the local Postmaster. This is not necessarily the same as the cutoff time for acceptance of all other packages. Check with the USPS Service Commitments page for exact commitments.

Media Mail

If you value price over the speed of transit, the USPS offers Media Mail as a very cost-effective way to send books, film, audio, other recorded media, or any of the items listed below. The Media Mail postage cost is determined based on only the weight of the mailpiece. The usual transit time for a Media Mail package is from 2 to 9 days, depending on the destination.

Media Mail rates are based on weight and size, not the zone-based, distance system that Retail Ground, Priority Mail, and Priority Mail Express use. If your mailpiece weighs less than 8 ounces, it will be less expensive to ship your item First-Class Mail. If it weighs more than that, print postage using the Media Mail option in Stamps.com.

  • Maximum Size: Length + 2 x Width + 2 x Height cannot exceed 108"

  • Weight: Up to 70 lbs.

Using Media Mail with Stamps.com

The best option for printing postage for Media Mail is to print shipping labels. You can print addresses, postage, and tracking information in one step. This method allows you and your recipient to track the package during transit.

If you don't need tracking and intend to address your package yourself, you can use NetStamps. You can save and use NetStamps at your leisure, as you would normal postage stamps.

Special Services Available with Media Mail

You can use the following special services with Media Mail:

USPS Media Mail Restrictions

The following restrictions apply to shipping Media Mail packages:

  • Dimensions: The sum of the package's length, width (2X), and height (2X) cannot exceed 108".

    • For example: (length = 21, height = 20, and width = 20).

      Sum = Length: 21 + height: 20 (x2 sides = 40) + width: 20 (x2 sides = 40): 101 inches is an acceptable size.

  • Max weight: 70 lbs.

  • Must be marked as Media Mail.

    If you are using shipping labels, the label will clearly identify the mailpiece as Media Mail.

  • Mailpieces can include ONLY the following (no other kind of material can be sent via Media Mail):

    • Books of at least 8 pages

    • Film (16mm or narrower)

    • Video recordings (Including, but not limited to, VHS and DVD)

    • Sound recordings (including, but not limited to, LP, cassette tape and CD)

    • Loose-leaf pages and binders of medical information

    • Printed music (bound or sheet)

    • Printed educational or test materials

    • Playscripts, screenplays or manuscripts

    • Printed educational reference charts

    • Computer-readable media (CD, DVD, etc.)

  • Any such material cannot include any advertisements except for incidental announcements of upcoming titles.

  • Sound recordings can include guides or scripts made specially for the recording.

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