If you’re moving, especially if you’ll be moving a long distance, renting an enclosed U-Haul trail is an excellent option.
Enclosed trailers protect your items from weather and potential theft, and they can be attached to your own truck, SUV, or even your car.
They’re also a less expensive option than a moving company. However, it can sometimes be difficult to fit larger items, such as a king mattress, into a trailer.
Learning about your options can help you choose the best trailer or moving solution for your situation.
Will a king-size mattress fit in a 5 by 8 trailer?
A standard king-sized mattress is 76 inches wide and 80 inches long, which equals 6 feet 4 inches wide by 6 feet 8 inches long. A 5 x 8-foot trailer is 8 feet long, 5 feet tall, and has a width of just under 5 feet.
Taking all of these sizes into consideration shows that the mattress could fit length-wise, as the trailer is deep enough. However, whether you lay the mattress down or stand it up, it will be too wide to fit into the trailer.

An option that may work is to position the mattress diagonally. Given the exact specification for a U-Haul trailer of this size, we can find that the diagonal of the trailer, from one top corner to the opposite bottom corner, would be ever so slightly over 80 inches, which means that the mattress would fit.
Transporting a mattress diagonally, however, means that you’ll have smaller spaces around the mattress in which to fit other items.
When you’re considering whether a mattress will fit in a trailer, it’s important to remember that the interior of the trailer is often slightly smaller than the exterior dimensions.
In addition, some trailers have a smaller door opening or a lip around the edge that can reduce the useable space or make it harder to get a mattress into the trailer.
To get a mattress of this size through the door opening, it will need to be bent as the opening will be too small unless it will fit diagonally.
California king mattresses have different dimensions than standard king mattresses. California kings are 84 inches long but only 72 inches wide, so it’s often easier to transport a California king in a 5 by 8-foot trailer, as long as the mattress is positioned diagonally.

Can I bend a mattress?
If it’s a tight fit to get your king mattress into a trailer, you may wonder if you can bend the mattress to make it fit. Although this is an option, most mattress companies do not recommend folding a mattress, even a little bit.
Traditional mattresses are made with metal springs and foam. If the springs are bent, it can be very difficult to get the springs back into the correct position.
Standard mattresses also often have border rods, and these can be bent and damaged if the mattress is folded.
The foam surrounding the bars and springs can also be torn, twisted, or otherwise damaged if a mattress is folded.
If you absolutely have to fold a mattress, make sure that you fold it as little as possible, and don’t leave it folded for a long time. Folding a mattress should only be done during very short trips.
Some newer mattresses aren’t constructed in the same way as traditional mattresses, and these mattresses can be folded in half or even rolled without damage.
Before folding or bending a mattress, always consult the user’s manual or contact the company for more information about whether the mattress can be bent without sustaining damage.

What else should I know about transporting a mattress?
Once you know whether your mattress will fit in a trailer, it’s a good idea to take a few steps to protect the mattress in transit. You can use a mattress bag to protect the mattress from dirt while traveling.
If a mattress bag isn’t available, you can wrap the mattress in a plastic drop cloth or use old sheets.
If the mattress moves around in the trailer, you may want to consider securing it with rope or straps. This will protect the mattress and any other items you’re transporting, and it can also help to balance your load.
However, the straps shouldn’t be too tight, as they can cause the mattress to bend, damaging the mattress.