King Short Mattress Toppers

Viscosoft's king short topper measures 75 by 74 inches, which is 75 wide and 74 long. That is one inch narrower than a standard king and one inch shorter than a twin, so it is a king-width bed with a twin-length limit. It is sold as both king short and short king, and most of these beds are in RVs.

No. An RV king is usually 72 by 80 inches. A short king is shorter, and its width depends on the brand: Viscosoft cuts 75 by 74, while many others sell 72 by 75. A cal king at 72 by 84 is different again. With this many king-named sizes around, a tape measure is the only reliable guide.

No. The Viscosoft king short topper is 75 by 74, so on a 72 by 75 mattress it hangs three inches over the side and stops one inch short at the foot. The overhang is the real problem, because the edge drops off the bed instead of lying flat. If you are not sure which you have, the topper finder walks through it.

It will not lie flat. A regular king topper is 76 by 80 inches, one inch too wide and six inches too long for a king short bed. The extra length folds up at the foot or bunches against the headboard, and in an RV there is rarely room for it to hang over. The king short topper is cut for the shorter frame.

You can cut the foam, but it rarely works out. An electric carving knife gets through memory foam cleanly, yet the removable cover is still sized for a full king and will not fit the trimmed piece. Cutting will also likely rule out a return, so check the returns policy first. A topper already cut to 75 by 74 arrives with its cover fitted, which is the simpler route.

They come close, but not quite. Two twin toppers side by side measure 76 by 75, one inch over in each direction. You also feel the seam down the middle, and the two pieces drift apart over time. Two twin XL toppers make a split king instead, which is a longer bed.

For width, yes. A 75 inch bed gives each person 37.5 inches, almost the same as a standard king and well ahead of the 30 inches each on a queen. Length is the catch. At 74 inches the bed is shorter than a twin, so anyone close to six feet has little room at the foot, and a topper cannot add length.

Measure the width first. Around 60 inches is a short queen, around 72 is another brand's short king or an RV king, around 75 matches the Viscosoft king short, and 76 is a standard king. Then check the length: 74 or 75 inches is a short bed, 80 is full length.

Yes, if you can. A stored RV gets cold and damp, and foam soaks up moisture, which leads to mildew and a musty smell. Cold also stiffens memory foam. Roll it loosely and keep it somewhere dry in a breathable bag rather than plastic, and remember it will not squeeze back to the size of the box it came in. The care guide covers washing the cover before it goes back in.