Working with US Postal Service (USPS) is integral for many, as their mandate to deliver to all US addresses allows eCommerce SMBs to reach their customers no matter where they live. However, it’s important to be familiar with USPS’ conditions for carriage — specifically paying mind to the USPS shipping restrictions and list of prohibited items.
By being mindful of items prohibited by the USPS and couriers shipping restrictions, you can ensure that you remain in good standing with your post office, and most importantly, that your packages are able to be shipped to their final destination. But you don't have to do it alone. Third-party services like Easyship are here to help you navigate USPS shipping restrictions and whatever the world of logistics management throws at you.
USPS Shipping Restrictions
If an item is restricted, it means that it can be shipped — but your shipment must meet USPS requirements, in addition to all federal, state and local laws that apply to the restricted item before its deemed acceptable for USPS shipping.
In particular, California is worth mentioning regarding their shipping restrictions, especially since the state accounts for 10.7% of the total US shipments.
California won't allow shipping of the following items that are tagged as restricted:
- Flammable and dangerous goods
- Animals and plants
- Guns, ammunitions and weapons
- Raw materials
- Monetary, bank notes and other valuables
- Automotive parts and accessories
- Perishable items, food, medicine and liquid items
USPS Restricted Items
- Intoxicating liquors
- Knives and sharp instruments
- Liquids, powders, and odor-producing materials
- Motor vehicle master keys and locksmithing devices
- Controlled substances and drugs
- Unsolicited promotional samples
- Building construction material
- Animal-fighting ventures
- Cigarettes and smokeless tobacco
The list is subject to change due to current events, like the pandemic and there are specific USPS Covid-19 shipping restrictions. After all, we know that 2020 isn't following the script.
Domestic USPS Shipping Restrictions
|Service||Length & Girth Combined||Max Weight|
|First Class Mail||108" (274 cm)||13 oz (368 g)|
|Priority||108" (274 cm)||70 lbs (31 kg)|
|Express||108" (274 cm)||70 lbs (31 kg)|
|Parcel Select||130" (330 cm)||70 lbs (31 kg)|
|Library Mail||108" (274 cm)||70 lbs (31 kg)|
|Media Mail||108" (274 cm)||70 lbs (31 kg)|
|Standard Post||130" (330 cm)||70 lbs (31 kg)|
USPS Shipping Restrictions by Size
Large Envelopes / Flats
If you are using a large envelope or flat, USPS shipping restrictions due to size come into play. Your item must be a maximum of 15 x 12 x .75 inches
If you are shipping a parcel, USPS package size restrictions mandate that the item must be, at the minimum, at least 3 x 6 x 1.4 inches thick.
USPS Media Mail Restrictions
You can use Media Mail to send media and educational materials, such as:
- Books (at least eight pages)
- Printed music and test materials
- Video and sound recordings
- Printed educational charts
- Medical loose-leaf pages and binders
- Computer-readable media
Items that do not qualify as media include:
- Video games
- Computer drives
- Digital drives
USPS Shipping Restrictions for Priority Mail
Priority mail is USPS’s domestic service which aims to deliver your parcel between one-three business days.
As mentioned earlier, USPS priority mail size restrictions dictate that no parcel can measure more than 108 inches in length and girth combined, and the maximum weight is 70 pounds.
If you are using the Priority Mail flat rate options, the contents of your shipment must easily fit inside the given box without needing to make any extra modifications. Items that are on the USPS shipping restrictions list or contain hazardous materials must meet all postal service requirements.
USPS Shipping Restrictions for First-Class Mail
The First-Class Mail service is advertised as an affordable way to send lightweight packages.
USPS First Class package restrictions are that large envelopes and parcels must have a maximum weight of 13 oz.
USPS Shipping Restrictions for Flat Rate mail
You may be familiar with the tagline: “If it fits, it ships.”
Considering the nature of flat rate shipping, this means there are relatively few USPS shipping restrictions on flat rate boxes and envelopes.
When you use a USPS flat rate box or envelope, there is no weighing or calculating required — as long as your parcel weighs under 70 pounds.
USPS Shipping Restrictions for Liquids
The USPS shipping rules state that liquids that are non-hazardous can be mailed as long as they are properly packaged. This means as long as it won’t risk damaging other mail or equipment, it's fair game.
Packaging requirements for non-hazardous liquids include:
- Containers with friction-top closures must be packed within a strong and securely sealed outer packaging.
- Liquids must be in a container that uses screw caps (minimum 1.5 turns), soldering clips, or other effective means to ensure full closure.
- Glass and other breakable containers more than 4 fluid ounces and any containers over 32 fluid ounces must be cushioned within a sealed, waterproof container such as a can or a plastic bag, and must be packed within a strong and securely sealed outer packaging.
- Steel pails and drums with carrying handles and positive closures (e.g., locking rings or recessed spouts under screw — cap closures) may be accepted without additional packaging.
USPS shipping liquid restrictions include liquids that are corrosive, explosive, flammable, toxic, or otherwise hazardous. These have special requirements for shipping, or may be prohibited. And while we briefly touched on USPS shipping restrictions in COVID times, we have just one more to add here. The question on everyone's mind: Can you ship the liquid-like hand sanitizer?
USPS APO Restrictions
If you are shipping to a military base, you can use the special Priority Mail APO/FPO large flat rate box. Just like the other flat rates, USPS APO shipping size restrictions are that the parcel cannot weigh more than 70 pounds.
Other parcels that are mailed from the continental US and airlifted to overseas Military Post Offices outside the continental United States must be no more than 15 pounds and no larger than 60 inches in length and girth combined.
USPS International Shipping Restrictions
Items with international USPS shipping restrictions include:
- Medical Devices
- Lithium Batteries
- Medicine or Drugs
USPS Restricted Countries
USPS will not deliver to countries that are currently sanctioned by OFAC, unless you have a special permit from OFAC to do so.
USPS international shipping restrictions by country
- The Balkans
- Central African Republic
- Democratic Republic of the Congo
- North Korea
- Sudan and Darfur
- South Sudan
- Ukraine (Crimea) / Russia
Size Restrictions for International USPS Shipping
Below are the following weight restrictions for the Priority Mail International services:
|Priority Mail International||70 lbs|
|Priority Mail International Flat Rate Envelope||4 lbs|
|Priority Mail International Small Flat Rate Box||4 lbs|
|Priority Mail International Medium Flat Rate Box||20 lbs|
|Priority Mail International Large Flat Rate Box||64 oz|
|First Class Package International Service||20 lbs|
|Express Mail International||70 lbs|
Remember that when using Priority Mail International Flat Rate options, the contents of your shipment must easily fit inside the given box without making any extra modifications.
USPS Prohibited Items
If an item is prohibited, it means it is strictly not allowed to be shipped by the USPS. Service will automatically be denied if your shipment’s contents are prohibited. If you weren’t honest about the contents of your shipment and USPS finds out, they have the right to suspend or close your account.
USPS shipping prohibited items for all shipments include:
- Air bags
- Marijuana (medical or otherwise)
USPS International Shipping Prohibited Items
The following items are prohibited for all international destinations:
- Air Bags
- Alcoholic Beverages
- Dry Ice
- Fresh Fruits and Vegetables
- Marijuana (medical or otherwise)
- Nail Polish
- Perfumes (containing alcohol)
It’s also important to note that every country has their own import laws and agreements with the US, so additional items may be prohibited for international USPS shipping depending on the destination country.
USPS’ Index of Countries and Localities is a great tool to help you discover specific prohibited items you may encounter when shipping cross-border. By clicking on the country you want to ship to, you’ll be able to see a full list of specific import prohibitions.
Prevent USPS Shipping Issues by Understanding USPS Shipping Restrictions
Hopefully your eCommerce inventory isn’t on the USPS forbidden items list! But if they are, be sure your shipment meets Postal Service requirements, in addition to all federal, state, and local laws that apply.
Also, we highly recommend against being dishonest about your shipment contents on your USPS label and paperwork. Not only can this put your account at risk for suspension or closure, but your business will be at risk of getting heavily fined by the countries you are importing to. For a list of the most recent rates in 2020, check out or blog post.
By paying attention and following USPS’s shipping restrictions, you can ensure your shipment will be allowed to ship and be delivered safely to your customer.
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