Mailing Standards of the United States Postal Service Domestic Mail Manual > 600 Basic Standards For All Mailing Services

601Mailability

Overview

1.0 General Standards

2.0 RESERVED

3.0 Packaging

4.0 Acceptable Mailing Containers

5.0 Handling, Content, and Extra Service Markings

6.0 Mailing Containers—Special Types of Envelopes and Packaging

7.0 Packaging Standards for Mail Processed at Network Distribution Centers

8.0 Hazardous, Restricted, and Perishable Mail

9.0 Written, Printed, and Graphic Matter Generally

There are five mail processing categories for mailpieces: letter, flat, machinable parcel, irregular parcel, and nonmachinable parcel. USPS assigns each mailpiece to one of these categories based on the physical dimensions and characteristics of the mailpiece using the longest dimension as the length, regardless of the placement or orientation of the delivery address on the piece. See the physical standards for processing categories in 101 for retail (single-piece price) mail and 201 for Commercial Mail.

Determine the processing category (see 1.1.1) based on the physical dimensions and characteristics of the mailpiece, without regard to address placement. Then, determine length and height as follows:

Letter-size pieces. For the purpose of determining mailability or machinability (see 1.1.3 Flat-size pieces. The length of a flat-size mailpiece is the longest dimension. The height is the dimension perpendicular to the length. Parcels. The length is the longest dimension. Customized MarketMail pieces. See 201.9.0

The placement of the address on a letter-size mailpiece may render a piece nonmailable or nonmachinable. If the length (the dimension parallel to the address) of a letter-size mailpiece is not at least 5 inches, it is nonmailable. If the height (the dimension perpendicular to the length) of a letter-size mailpiece is not at least 3-1/2 inches, it is nonmailable. If the aspect ratio (length divided by height) is not within 1.3 to 2.5 (inclusive), the piece is a nonmachinable letter. For example:

The Postal Service maximum mailpiece weight limit is 70 pounds (see 201.7.3). Any item exceeding the 70-pound maximum is nonmailable and if found in the postal network, must be secured for pick-up by the mailer or addressee and assessed a fee under 1.2.3.

The standard in 1.2.1 applies to any item that exceeds the 70-pound weight limit including return services, return to sender, and undeliverable as addressed. The standard in 1.2.1 for items exceeding the 70-pound weight limit does not apply to the Competitive PO Box Street Addressing feature in DMM subsection 508.4.5.4.

Except for an overweight item discovered and picked up at the same facility where it was entered, the overweight item fee of $100 will be assessed and must be paid before release of the item. The $100 overweight item fee may be paid by any authorized retail payment method.

Unless authorized, an overweight item not paid for and picked up within 14 calendar days will be considered abandoned and disposed of at the discretion of the Postal Service.

Articles presented for mailing must be prepared under the general and specific standards in this document. The USPS accepts properly packaged and marked parcels but reserves the right to refuse nonmailable or improperly packaged articles or substances. Additional or other standards can apply to overseas military Post Offices and international mail.

It is the mailer’s responsibility to refrain from depositing nonmailable matter in the mail. The mailer must comply with applicable postal laws and regulations governing mailability and preparation for mailing, as well as nonpostal laws and regulations on the possession, treatment, transmission, or transfer of particular matter. Information about USPS standards is available from postmasters, business mail entry managers, and the PCSC manager (see 608.8.0).

Mailers must package mailpieces to withstand normal transit and handling without breakage or deterioration of content, package breakage, injury to USPS employees, or damage to other mail. See 3.2 through 3.8 for specific types of items. Mailers must follow these additional standards for packaging:

Stationery-type items thicker than 1 inch or heavier than 1 pound are not accepted in letter-style envelopes. The contents of these packages must be secured by tying, banding, or using partitions on close-fitting interior containers to prevent shifting.

Pens, pencils, key rings, bottle caps, and other similar odd-shaped items are not permitted in letter-size or flat-size paper envelopes unless they are wrapped within the other contents of the envelope to streamline the shape of the mailpiece and prevent damage during postal processing. If an odd-shaped item is not properly wrapped, it could burst through the envelope and cause injury to employees and damage to USPS processing equipment. Odd-shaped items that are properly wrapped within paper envelopes and sent at letter prices may be subject to the nonmachinable surcharge under 133.1.5 or 233.1.4 for First-Class Mail letters, or the nonmachinable prices under 243.5.5 for USPS Marketing Mail letters. Certain types of odd-shaped items, when properly wrapped, are permitted as automation letter-size mail subject to the standards in 201.3.10. Flat-size automation mail is subject to the uniform thickness requirement in 101.2.4.

Mailers must mark the outer container of a mailpiece containing liquid to indicate the nature of the contents (i.e. liquid), and include orientation arrows in accordance with Publication 52, section 226. Mailers must package and mail liquids under the following conditions:

Aerosols (containers under pressure) are hazardous materials and must be constructed to prevent accidental discharge of the contents during postal handling. Mailable aerosol containers must be packaged under Publication 52, (PUB 52) part 342.

Mailpieces containing perishable, hazardous (including infectious substances), biological, or restricted materials are subject to the standards in PUB 52.

High-density items are solid objects (such as tools, hardware, and machine and auto parts) whose weights are comparatively high for their volumes. Package high-density items weighing more than 15 pounds so that the contents do not exert more than 60 pounds per square foot on the smallest side of the mailing container.

The following three terms describe types of loads, based on content, degree of protection, and strength of the mailing container.

An easy load contains items of moderate density that either completely fill the mailing container or are packaged in interior containers that completely fill the mailing container. Easy load items are not easily damaged by shock, compression, or puncture. An average load contains moderately concentrated items packaged directly into a mailing container. Mailers can prepackage average load contents by nesting items within partitions or in separate paperboard boxes to stabilize items to prevent shifting and damage. A difficult load contains items that require a high degree of protection to prevent shock, puncture, or distortion to the items or the mailing container. The Postal Service does not accept in paperboard boxes, bags, or wraps difficult loads such as fragile items; delicate instruments; and high-density, small-bulky items.

Loose-fill cushioning must overfill the container before closure to hold the item and prevent its movement within the container. When multiple items are inside a single mailing container, mailers must cushion items to protect them from each other as well as from external forces. Do not package high-density heavy items with fragile items unless extreme care is taken to separate them from each other. Mailers must adequately stabilize heavy items within the package.

A strong packaging or paper tape (not cellophane or masking tape) may be used for the closure or reinforcement of packages. Paper tape must be at least 60-pound basis weight kraft. The adhesives on gummed tapes must be adequately activated before application and firmly applied with the tape extending at least 3 inches over the adjoining side of the box. Except for pressure-sensitive filament tape, tapes used for closure and reinforcement should be at least 2 inches wide. Nonreinforced plastic tapes must be at least as strong in the cross direction as in the machine (long) direction.

Adhesives used for closure on box flaps or on tapes must remain serviceable from -20 degrees to +160 degrees Fahrenheit. When using hot-melt adhesive, apply adhesive using one of these methods:

When banding is used for closure and reinforcement, it must encircle the length and girth of the package at least once. Twine or cord should not be used for closure and reinforcement, as it could interfere in mail processing equipment. Loose strapping and metal strapping are not acceptable.

Mailers may use staples or steel stitching to close boxes as follows:

Mailers must prepare envelopes according to the following weight limits and conditions:

Boxes are acceptable, subject to these standards:

Mailers may use fiberboard tubes and similar long containers for mailing if the containers meet the following requirements:

For easy loads of up to 5 pounds, paper bags and wraps are acceptable when at least of a 50-pound basis weight (the strength of an average large grocery bag) and the items are immune from impact or pressure damage. A combination of plies adding up to or exceeding 50-pound basis weight is not acceptable. For easy and average loads of up to 20 pounds, reinforced bags or bags with a minimum of 70-pound basis weight are acceptable. Nonreinforced loose-fill padded bags are not acceptable as exterior containers, unless the exterior ply is at least 60-pound basis weight.

Plastic bags must be at least 2 mil thick polyethylene or equivalent for easy loads up to 5 pounds; 4 mil thick for easy loads up to 10 pounds.

Heat-shrinkable plastic film—either irradiated polyethylene, linear low-density polyolefin, or copolymer—may be used as packaging for mailpieces under the following conditions only:

Cloth bags are acceptable for easy and average loads of up to 10 pounds, if the seams of the bags equal the strength of the basic material.

The USPS does not accept bags, bales, or wraps with difficult loads. The contents in bags, bales, and wraps must be compressed when possible.

Bales are acceptable within postal weight limits, if adequately compressed and reinforced to contain the material.

Mailers may mail items in cans and drums with positive closures (such as clips). Friction closures alone are not acceptable. Mailers must shield protruding devices, such as locking rings, with padding material to prevent injury to USPS employees and damage to equipment or other mail.

Certain markings may be used to identify handling, content, and extra service. Unauthorized markings not designating price, class, address, handling, content, or extra service are not permitted. Extraneous information, which can be confused with ZIP Codes, may not be placed next to or directly under the last line of the delivery address. Any obsolete marking on a container to be reused for mailing must be obliterated. The following markings must be placed in an area below the postage and above the addressee’s name in the delivery address and to the right of the return address:

The mailer must mark the package using material that is not readily water soluble or easily smeared or rubbed off. The marking must be readable at a distance of 30 inches. Marking methods or surfaces must permit application and retention of adhesive stamps, postage meter impressions, and postal endorsements. Any address label or envelope must be firmly affixed to the mailing container, with no more than a 1/8-inch separation between the ends of the label or envelope and the container.

Priority Mail Express and Priority Mail packaging provided by the USPS must be used only for Priority Mail Express or Priority Mail, as applicable. Regardless of how the packaging is reconfigured or how markings may be obliterated, any matter mailed in USPS-provided Priority Mail Express or Priority Mail packaging is charged the appropriate Priority Mail Express or Priority Mail price.

An envelope or card bearing a green diamond border must be used only for First-Class Mail. Any envelope or card bearing a green diamond border is charged the appropriate First-Class Mail price, regardless of mail content or of requested class or service. When printed on letter-size mail, the border must not enter the OCR read area or barcode clear zone unless a delivery point barcode appears in the address block as described in 202.5.3.

For all letter-size and flat-size mail in window envelopes, every character in the delivery address, including any postal barcode, marking, or endorsement, must be completely visible through the window throughout the full range of movement of the insert bearing the delivery address. Any window envelope used for letter-size or flat-size mail claimed at automation prices or for letter-size mail claimed at Enhanced Carrier Route high density or saturation prices must also meet the barcoding standards for letters and flats in 204.1.0. Any window envelope used for letter-size or flat-size mail must meet the following additional standards:

A reusable mailpiece is an envelope, self-mailer, or similar mailpiece designed for two-way mailing. The recipient removes part of the original mailpiece or refolds the piece to cover the delivery address of the recipient and reveal the delivery address of the originator (sender) for return. Except for reusable mailpieces that originate as permit imprint mailings, the piece must meet these standards:

The piece must be designed and constructed so that the recipient may reconfigure or modify it to remove or obscure the address that applied to the piece when it was originally mailed. The instructions on the piece must ensure that the recipient can prepare the piece correctly for remailing. If a reusable piece does not meet the applicable standards, the piece must be re–enveloped and new postage affixed before distribution by the originator.

When reusable mailpieces are originally mailed, postage must be paid with permit imprint and a complete address and corresponding barcode must be located in the address block. Reusable pieces must be entered at a postal facility as part of a permit imprint mailing. On mailpieces other than window envelopes, the address block for return of the piece (including the delivery address and a corresponding barcode) will be located on the reverse side. If included, prepaid reply postage must be located or obscured so that it is not mistaken by postal mail processing equipment or employees as applying to the originating piece.

When the piece is reconfigured for return from the recipient to the originator, only one complete address with a corresponding barcode located in the address block and a FIM must be visible on the piece. If a reusable mailpiece does not meet the applicable standards, the piece must be re–enveloped and new postage affixed before return by the recipient.

When the permit imprint indicia for USPS Marketing Mail or First-Class Mail is printed on a reusable window envelope intended to be returned as Business Reply Mail (BRM), the imprint “NO POSTAGE NECESSARY IF MAILED IN THE UNITED STATES” must be printed on the envelope directly below the permit imprint indicia. See Exhibit 6.5.4 below. These additional conditions apply:

Exhibit 6.5.4 Outgoing and Return Two-Way Indicia Examples

High-density items (see 3.7) weighing from 20 to 45 pounds must be packaged in fiberboard boxes constructed of a minimum 200-pound test board or equivalent wood, metal, or plastic containers. Plastic, metal, and similar hard containers must be packaged, treated, or otherwise prepared so that their coefficient of friction or ability to slide on a smooth, hard surface is similar to that of a domestic-class fiberboard box of the same approximate size and weight. Closure must be done by staples, heat-shrinking, adhesives, or tape. Boxes without inner packing or containing loose material must be reinforced or banded with reinforced paper or plastic tape, pressure-sensitive filament tape, or firmly applied nonmetallic banding. Internal blocking and bracing, including the use of interior containers, cut forms, partitions, dunnage, and liners, must be used as required so that packages are capable of maintaining their integrity without damage to the contents if dropped once on one of their smallest sides on a solid surface from a height of 3 feet. These items from 45 to 70 pounds must be similarly packaged, closed, and reinforced, except that exterior containers must be a minimum of 275-pound test fiberboard or equivalent.

Books and similarly-produced printed matter (such as catalogs) fastened together along one edge between hardback, paperback, or self-covers, that are more than one inch thick or one pound must not be accepted in letter-style non-reinforced flat envelopes or without packaging. Envelopes or other appropriate packaging must meet the standards in 3.0. Void spaces within containers must be filled with dunnage, or otherwise stabilized to prevent shifting or damage to the contents or container. Shipments are packaged according to the following weight categories:

Boxes containing soft goods (e.g., textiles, clothing, linens, or draperies) weighing up to 5 pounds must be filled to capacity. Soft goods between the weight range of 5 to 20 pounds must be packaged in material with a minimum 70-pound outer ply basis weight. Closure of bags must be by completely clinched staples, heat-sealing, adhesives, sewing, or tape. Improperly clinched staples must be removed. Shrinkwrapping is not acceptable as the only packaging. Fiberboard containers must be made of at least 200-pound test board for soft goods weighing from 20 to 45 pounds and at least 275-pound test board for soft goods weighing from 45 to 70 pounds.

Shipments of recordings (e.g., records and CDs in paper sleeves, paperboard, or chipboard shells) weighing up to 10 pounds must be packed in 70-pound basis weight envelopes for weights up to 3 pounds, or outer corrugated, fiberboard containers for weights up to 10 pounds. When shipments weigh from 20 to 40 pounds, multiple shell containers must be packaged in 175-pound test fiberboard containers or equivalent and closed and reinforced by adhesives, kraft paper tape, equivalent plastic tape, or staples. When shipments weigh from 40 to 65 pounds, multiple shell containers up to 65 pounds must be packaged in 200-pound test fiberboard containers or equivalent and closed and reinforced as described for 20- to 40-pound containers, except that containers must be reinforced about every 8 inches around the package. Shipments weighing more than 65 pounds must be packaged in 275-pound test fiberboard containers or equivalent.

Effective July 7, 2014, all content applicable to hazardous, restricted, or perishable mail was removed and incorporated into Publication 52, Hazardous, Restricted, and Perishable Mail. Publication 52 can be found on the Postal Explorer website at pe.usps.com.

Hazardous material is any article or substance designated by the U.S. Department of Transportation (DOT) as being capable of posing an unreasonable risk to health, safety, and property during transportation. The provisions concerning hazardous material moved to Publication 52, chapter 3, include mailability restrictions and instructions for:

Restricted matter is an article or substance prohibited or limited by title 18 of the U.S. Code. It also includes matter not otherwise restricted by 18 USC 1716(a) because it may, under conditions encountered in the mail, be injurious to life, health, or property. Examples of the type of restricted matter content moved to Publication 52, chapter 4, include:

Perishable matter is anything that can deteriorate in the mail and thereby lose value, create a health hazard, or cause an obnoxious odor, nuisance, or disturbance, under ordinary mailing conditions. Mailable perishable matter may be sent at the mailer’s own risk when it is packaged as required and when it can be delivered within appropriate and reasonable time limits to prevent deterioration. Examples of the type of perishable matter content moved to Publication 52, chapter 5, include:

Any otherwise mailable matter that reasonably could be considered a bill, invoice, or statement of account due, but is in fact a solicitation for an order, is nonmailable unless it conforms to 9.1.2 through 9.1.5. A nonconforming solicitation constitutes prima facie evidence of violation of 39 USC 3005. Compliance with this section does not avoid violation of Section 3005 if any part of the solicitation or any information with it misrepresents a material fact to the addressee (e.g., misleading the addressee about the identity of the sender of the solicitation or about the nature or extent of the goods or services offered may be a violation of Section 3005).

The solicitation must bear on its face either the disclaimer required by 39 USC 3001(d)(2)(A) or the notice: “THIS IS NOT A BILL. THIS IS A SOLICITATION. YOU ARE UNDER NO OBLIGATION TO PAY THE AMOUNT STATED ABOVE UNLESS YOU ACCEPT THIS OFFER.” The statutory disclaimer or the alternative notice must be displayed in conspicuous boldface capital letters of a color prominently contrasting with the background against which it appears, including all other print on the face of the solicitation and that are at least as large, bold, and conspicuous as any other print on the face of the solicitation, but not smaller than 30-point type (see Exhibit 9.1.2). The notice or disclaimer required by this section must be displayed conspicuously apart from other print on the page immediately below each portion of the solicitation that reasonably could be construed to specify a monetary amount due and payable by the recipient. It must not be preceded, followed, or surrounded by words, symbols, or other matter that reduces its conspicuousness or that introduces, modifies, qualifies, or explains the required text, such as “Legal Notice Required by Law.”

Exhibit 9.1.2 Solicitation Disclaimer

The notice or disclaimer must not, by folding or any other device, be made unintelligible or less prominent than any other information on the face of the solicitation.

If a solicitation consists of more than one page or if any page is designed to be separated into portions (e.g., by tearing along a perforated line), the notice or disclaimer required by 9.1.2 must be displayed in its entirety on the face of each page or portion of a page that might be reasonably considered a bill, invoice, or statement of account due as required by 9.1.2.

For this standard, color prominently contrasting excludes any color, or any intensity of an otherwise included color, that does not permit legible reproduction by ordinary office photocopying equipment used under normal operating conditions, and which is not at least as vivid as any other color on the face of the solicitation; and color includes black.

Any solicitation stating that it is approved by the USPS or the Postmaster General or that it conforms to any postal law or regulation is nonmailable.

A solicitation that misrepresents a government entity is nonmailable subject to these conditions:

A solicitation described in 9.2.2a may be mailable if it meets at least one of these conditions (see Exhibit 9.2.3b):

Exhibit 9.2.3b Disclaimers for Solicitations Implying Federal Connection

For this standard, lottery is any scheme or promotion, whether lawful under the laws of any state, which, on paying a consideration, offers a prize dependent in whole or in part on lot or chance.

Unlawful matter includes any letter, newspaper, periodical, parcel, stamped card or postcard, circular, or other matter permitting or facilitating participation in a lottery; any lottery ticket or part thereof or substitute; and any form of payment for a lottery ticket or share.

This standard does not apply to:

Any advertising, promotional, or sales matter that solicits or induces the mailing of any article described in PUB 52 as hazardous, restricted, or perishable is nonmailable except that such matter relating to controlled substances, radioactive materials, restricted liquids and powders, battery-powered devices, odd-shaped items in envelopes, and switchblade and ballistic knives, as described in PUB 52, is mailable if it contains packaging instructions and any other mailing limitations under PUB 52, 508.9.0, and 508.10.0 (18 USC 1716).

Advertisements for motor vehicle master keys are nonmailable (18 USC 1716A, 39 USC 3002), except to lock manufacturers, professional locksmiths, motor vehicle manufacturers or dealers; and federal, state, or local government agencies.

Matter addressed to a person using a fictitious name, title, or address in conducting, through the mail, any scheme or device in violation of law is nonmailable if:

Mail of foreign origin is nonmailable if it contains matter determined by a court of competent jurisdiction or by the International Trade Commission to violate the Semiconductor Chip Protection Act of 1984 (17 USC 901-914) or to violate the copyright laws of the United States or any copyright convention or treaty to which the United States is a party (17 USC 601-603).

Matter addressed to foreign countries posted in violation of law or treaty stipulation is nonmailable.

Obscene, lewd, lascivious, or filthy publications or writings, or mail containing information on where, how, or from whom such matter may be obtained, and matter that is otherwise mailable but that has on its wrapper or envelope any indecent, lewd, lascivious, or obscene writing or printing, and any mail containing any filthy, vile, or indecent thing is nonmailable (18 USC 1461, 1463).

Any matter of a character tending to incite arson, murder, assassination, treason, insurrection, or forcible resistance to any law of the United States, or containing any threat to take the life of, or to inflict harm upon, the President of the United States is nonmailable (18 USC 1461, 1717).

Other matter that is nonmailable (18 USC 1717) includes every letter, writing, circular, stamped card or postcard, picture, print, engraving, photograph, newspaper, pamphlet, book, publication, or thing as described in these statutes:

This standard does not pertain to written, printed, or graphic matter related to fighting ventures involving live birds if such fight is permitted under the laws of the state in which the fight is to take place (7 U.S.C. 2156). The terms animal, animal fighting venture, and state are defined in PUB 52, part 461. Written, printed, or graphic matter is nonmailable if it:

A private identification document without a disclaimer is nonmailable (18 USC 1738; 39 USC 3001(a)). This group includes any document that:

The term sweepstakes means a game of chance for which no consideration is required to enter.

Sweepstakes matter is mailable only if it discloses all of the following:

Sweepstakes matter is nonmailable if it does any of the following:

The term skill contest means a puzzle, game, competition, or other contest in which a prize is awarded, the outcome depends upon the skill of the contestant, and for which a payment, purchase, or donation is required to enter.

Skill contests are mailable only if they include all of the following:

A facsimile check is nonmailable unless it states on the face of the check that it is not a negotiable instrument and has no cash value.

Matter described in 9.6, 9.7, and 9.8 is mailable if it appears in a magazine, newspaper, or other periodical if the promotions are not directed to a named individual, or the promotions do not include the opportunity to make a payment or order a product or service.

Any notice or disclaimer required under 9.6, 9.7, and 9.8 shall be clearly and conspicuously displayed. Disclaimers required by 9.6.2a and 9.6.2b must be more conspicuously displayed than any other disclaimer.

In general, any person who uses the mails for any mailing falling under 9.2, 9.6, 9.7, and 9.8 shall adopt reasonable practices or procedures to prevent the mailing of such matter to any person who, personally or through their legal representative, submits a written request that no such matter shall be mailed to that person. Such request may be made either to the mailer, or the Attorney General, or their representative, of the appropriate state. Such requests shall be honored for a period of five years from the date of the request. The mailer shall maintain a record of all such written requests.

Any promoter of sweepstakes or skill contests must make a clear and conspicuous disclosure of the address or toll-free telephone number by which an individual, or their duly authorized representative, may notify a promoter to have that individual‘s name and address removed from all lists of names and addresses used by that promoter to mail any skill contest or sweepstakes. Promoters have 60 days from the date of receipt of the removal request to effect the removal of the name and address from all mailing lists used by that promoter for any skill contest or sweepstakes.

Postmasters are not authorized to decide whether written, printed, or graphic matter is nonmailable based on its content or to deny entry to such matter or exclude it from the mail.

Written, printed, or graphic matter not properly prepared for mailing can be refused.