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Can You Use Duct Tape to Mail a Package? | Taping Rules

I was getting some packages together to mail and realized I was out of packing tape. The only thing I could find was some duct tape inside my toolbox. I was unsure if UPS, FedEx, or the postal service would accept a package with duct tape, so I made some calls, and this is what I found out.

Duct tape should not be used to seal a package you intend to mail. It does not stick well to cardboard. USPS and other shipping companies will usually not accept a parcel held together by duct tape.

Instead, you should always use packing tape, like this kind from Amazon.

Duct tape can be used for a great many things, but holding a package together during a turbulent voyage is not one of them.

Why Will Mailing Services Not Accept Duct Taped Packages?

A package wrapped in duct tape will not be accepted because it does not have the structure to hold a cardboard box together, nor does it adhere well to cardboard.

  • It doesn’t stick well- Duct tape will not stick to cardboard efficiently because cardboard is a porous surface. On the surface of cardboard, tiny fibers exist. These fibers will cause duct tape to pull away from the cardboard resulting in a failed adhesive bond.
  • Traveling hazard- Any pressure on the shipping journey can cause the duct tape to separate from the cardboard box. This can result in your mail opening in transit and the items in your package spilling out or being damaged before the parcel reaches its intended recipient.

Cardboard and duct tape’s failure to bond is the reason why people in the shipping industry will turn away these packages. By not sending these parcels, shipping companies protect their customers’ belongings while lowering their liability.

This is why packing tape is most often recommended to seal the seams of a package to keep the contents inside safe, not duct tape.

Types of Tape You Should Use to Mail a Package

When securing a parcel, USPS recommends sealing your cardboard box with one of these products:

They do not want you to use duct tape. Even though their website fails to identify it as one of the tapes not to use. In contrast, UPS does specifically mention not to use duct tape on your packaging.

Items That Should Not Be Used to Mail Your Packages

These products should not be used to ship parcels.

  1. Duct Tape
  2. Masking Tape
  3. Scotch Tape (cellophane)
  4. Electrical Tape
  5. Cord
  6. Twine
  7. String

These items either lack the strength to hold your package together or could clog the machinery used to sort mail.

What is the Difference Between Duct Tape and Packing Tape?

There are two parts to all tape; a material backing and an adhesive film. The material part of the tape can be referred to as a carrier.


Packing tape uses a durable plastic carrier, while duct tape’s carrier consists of low-density polyethylene (thermoplastic) that covers a fabric-based skim. This skim or fine-layered fabric film can be made from a wide assortment of materials, including polyester, nylon, rayon, and fiberglass mesh.

Adhesive Film

Duct tape is a flexible and robust tape that uses a rubber-based adhesive. It has multiple uses, from sealing ductwork to making costumes, with the backing being known to repel water. The strongest duct tape ever made can support 700+ lbs of weight. This duct tape’s name is T-Rex Brute Force. It supports more weight than filament packing tape.

Packing tape is much more restrictive than duct tape. The same force required to stretch duct tape will not stretch packing tape because it uses a hot melt adhesive. This is a stronger type of bond when compared to the adhesive used in cellophane tape. This makes it less stretchy but also allows it to stick better to certain surfaces.

Why Duct Tape Fails on Packaging

Duct tape bonds well with non-porous surfaces. You can use it on many different construction and plumbing projects; however, you should avoid putting it on concrete, stucco, and of course, cardboard. Duct tape does not work well on rough surfaces because it can only make contact with the high points of the surface. This makes getting a strong adhesive bond challenging.

When duct tape breaks down, the adhesive film can begin to separate from the carrier, and it does not stick to porous surfaces for long. It can leave a sticky residue when removed from these surfaces.

Packing tape’s adhesive generally does not come apart from its backing and can be used on porous surfaces. Therefore, it is the best thing to use on cardboard.

People often use two types of packing tape to seal boxes: standard (clear and brown) and filament (reinforced). Filament packing tape is stronger because it has been reinforced with fiberglass strips. This tape can support 100 to 400 lbs in weight.

Bottom Line

While duct tape and packing tape are both strong, the construction of each was intended for entirely different purposes. Packing tape works well on cardboard, while duct tape works well on almost everything else. That is why it is a good idea to have both of these products on hand, but make sure that you don’t substitute them.

I hope this article has been helpful. Thanks for reading!

For more, check out In Transit vs. Out for Delivery | What Do They Mean?