USPS M-Bag: Is it Useful for You?

M-bags are directly related to postal services. These are direct sacks that contain several printed matter or letters which can be sent to a single addressee. The pricing of M-bags depends solely on the number of contents in the sack and its weight. 

The more the weight and the contents of the M-bag, the greater is the price. M-bags travel utilizing air transportation. This is the basic introductory idea regarding USPS M-bags. Let us learn about it in prior detail. 



  • The maximum weight can be up to 66 pounds, which is the total weight of the contents and the sack. However, maximum weights vary in different countries. But for USPS M-bags specifically, the maximum weight of M-bags can be not over 66 pounds, which is around 30kgs. There is no available information for the minimum weight of the USPS M-bags. 
  • The availability of M-bags also depends on the reference listings of the postal services of an individual country. For listings of Airmail M-bags, Exhibit 293.45 is applicable for ISAL M-bags, and 292.45 is applicable for IPA M-bags. 
  • To identify an M-bag correctly, the all-important PS Tag of 158 (the M-bag Addressee Tag) is attached at the neck of the mail sack. 
  • To proper postage of Airmail USPS M-bags, PS Tag 158 applies to International Surface Air Lift (ISAL) and International Priority Airmail (IPA). 
  • For added services, a prior mailing certificate is available, but any services of insurance and registry are not applicable. 


Without any doubt, USPS Airmail M-bags are the most affordable and accessible way to send huge amounts of different kinds of printed materials worldwide. By printed material, we mean anything printed, including newspapers, directories, books, journals, commercial advertising, catalogs, magazines, and other promotional matters. Delivery pricing varies by weight of them-bag and the destination of them. The price of m-bags starts from 51.70 US dollars at any Post Office location all-over America. 

There is a different individual requirement for sending M-bags to other countries. The general conditions for mailing, size limits, prohibitions, observations, Global Express Guarantees, value limit, and insurance services differ for mailing M-bags in different countries. The whole detailed listing is available on the official website of the United States Postal Services. 

The general pricing of M-bags is divided into 9 price groups. The pricing varies from 26.95 US dollars to 44 US dollars, starting from the first price group to the last price group. 


This segment is to help to learn how to prepare for shipping international USPS M-bags. Check: USPS Shipping Estimate: The Complete Guide

But before we tell you the details, we should mention a very important notice. The USPS suspended every kind of international mail service temporarily to some destinations. The international Airmail services are suspended from 25th October 2021 for certain destinations as an essential measure due to the raging impact of the COVID-19 pandemic worldwide. 

The countries include Australia, Great Britain, Korea, Sweden, Switzerland, Thailand, Singapore, Spain, Japan, Israel, Hong Kong, New Zealand, Canada, France, and China. Some African countries also come under this list, including Sudan, Brunei, and Papua New Guinea. USPS will resume its services shortly after the pandemic loses its fury. 

Anyway, let us check the ways to send international mails via USPS. 

Check The Shipping Restrictions Many countries have different kinds of prohibitions when it comes to sending international M-bags. For this, you should have proper information on the prohibitions on the concerned country you are sending the M-bag, their designated country requirements, and prohibited items. All the information is available on their official website. 

Check The Allowed Weight And Size

It is very important to check the allowed size and weight before opting for sending Airmail M-bags. It is advisable to use standard-sized boxes and envelopes for it. Sometimes the mail item fails to fit the automated processing equipment; it either becomes non-machinable or costs much higher than the usual rates. 

There are factors on which an envelope can be considered as non-machinable. Some points are 

  1. Envelopes are too rigid.
  2. The ratio of length divided by height is more than 2.5 and less than 1.3.
  3. Wrapped by an outer material which is made of anything except paper. Poly wrapped or polybagged envelopes will be disqualified automatically.
  4. Envelopes of thickness less than 0.009 inches, height more than 4.25 inches, or length more than 6 inches will not qualify.

Now let us discuss the weight limits also. Weight limits for small flat rate priority mail international shipments can be up to 4lbs. 

Whereas the weight limits for large flat rates priority mail International shipments can be up to 20lbs. 

If you want your package to be shipped via the first-class international package service, then the weight of the package can be around 4lbs or less and can cost you about 400 US dollars.

Address The International Mail 

Do not forget to print or write the proper address you are mailing and your return address. This is one of the basic principles one should follow to get their mail delivered on time. 

To write the address properly 

  1. Print correct and complete addresses neatly in blocked letters.
  2. Use a permanent marker or pen.
  3. Refrain using periods or commas. 
  4. Mark your package as “Perishable” or “Fragile” when required.

Choose The Appropriate Shipping Service 

International mailbags can be sent through Priority Mail International Express, Global Express Guaranteed, Priority International Mail, First-class International Package Service, First-class Mail international, or Airmail M-bags. 

Create Labels And Customs Forms 

You have to fill a special customs form for international mailbags shipping. It is not required to send correspondence or non-negotiable documents weighing under 16 ox through First-Class International Mail. 

Apply Postage And Calculate 

Using the correct postages is essential as it helps your packages reach the correct address on time. The costs of shipping can vary as it depends on several factors. USPS provides its users with their postage calculator. Using that calculator, you can easily know the postage price of your concerned requirement. 

Send Your Shipment 

After the mailbox is ready and the payment is made, it is time to make the shipment. Drop your small-sized packages in the blue collection box visiting the nearest post office of your locality. 

Other than printed objects, tapes, discs, and cassettes are also deliverable via this service. Any other commercial articles that are non-dutiable and not subject to resale can also be sent using the USPS Airmail bags. 

However, the catch while sending these items is that it has to be something related to the printed matter along which they are going. 

These articles must be affixed or attached with the printed matter accompanying them. 

The criteria of weight is also a very important thing. Anything you send, the total weight (along with the box) should be 4lbs or less than that in weight. For ISAL and IPA M-bags, the importance of the articles and the accompanying printed matter can weigh only up to 4.4 pounds and should not exceed it. 

As already mentioned earlier, you can add a remark on your mailbox as “perishable” or “fragile,” if required, according to the contents of your mailbox. The M-bad should be accompanied by an electronically generated, fully completed PS Form 2976, and it has to be affixed or attached with the essential PS Tag 158.

Shipping guy at USPS, previously at Fedex.

Leave a Comment