RV King Mattress: Four Sizes Behind One Name, and the One Your Bed Takes
An RV king is narrower than the king at home, and one maker builds it in four different sizes.
Written from published maker size charts, never from first person testing.
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The Four RV King Sizes
RV builders shave inches off a king to clear a walkway or a closet, and each cut became its own size name.
King sizes from the Wilderness RV Mattress size guide, read October 2026
Swipe the table sideways to see every column.
| Size name | Width by length | Built for |
|---|---|---|
| RV Narrow Short King | 70" x 74" | RV bedrooms |
| RV Narrow King | 70" x 80" | RV bedrooms |
| RV Short King | 72" x 74" | RV bedrooms |
| RV King | 72" x 80" | RV bedrooms |
| California King | 72" x 84" | Household beds |
| Standard King | 76" x 80" | Household beds |
The two household sizes are there for comparison, because people searching for an RV king often own one of them already.
On the Wilderness chart a California king at 72 by 84 is four inches longer than the RV king, so it is almost never the answer in a rig.
Why One King Name Covers Several Sizes
No industry body fixed RV size names, so two specialists can sell different mattresses under one label.
At 72 by 80, the RV King is the one size both makers list under that name.
Mattress Insider also sells 70 inch wide kings as RV Kings.
On a short king, a single inch of extra length is enough to stop a mattress dropping into a tight frame.
RV King Against a Standard King
A household king is 76 inches wide and an RV king is 72, so the household mattress is too wide for most RV platforms.
Four inches sounds small until it is pressed against a wall or hanging over the walkway to the bathroom.
The same gap applies to bedding, so standard king sheets and mattress protectors bunch on an RV king and slip off a narrow one.
How to Measure for an RV King
Ordering to the size name is the avoidable mistake, because a mattress built to order is cut to the numbers you send.
Here is what to check before you order.
Measure the platform
Lift the old mattress off and tape the bare frame, since a used mattress has compressed and its cover has shrunk.
Use the smaller number
If one side reads shorter, go with that figure, because a snug fit beats one that will not drop in.
Note corners and notches
Wilderness says a 2 or 3 inch corner radius is typical, and a notch for a post or wheel well needs its width and depth.
Check the headroom
A slide that passes over the foot, or a cabinet over the head, caps how deep the mattress can be.
Those four numbers let you order a king from any maker without trusting a size chart.
Depth, Slides and Hinged Kings
Most RV king beds sit in a slide out, so the thickness of the mattress matters as much as its width.
10 to 11 inches
The deepest Wilderness king builds, per its size guide, for a platform with open headroom.
8 inches
The Wilderness Canyon depth, the safer choice where a slide or cabinet limits the gap.
Where the slide still catches the foot, Wilderness can add a hinge so that end of the mattress flips up when the room closes.
Its size guide also notes that a lower foot platform is common with slide outs, and it builds that section thicker so the top sits level.
Ordering an RV King Cut to Your Platform
Cut to order mattresses side step the naming problem, since you send measurements instead of a label.
Wilderness RV Mattress makes each mattress to order in South Carolina, cut to the whole inch, with king sizes in its Montana, Aspen and Canyon builds.
Wilderness ships free to the continental United States and covers each king with a 10 year warranty and a 100 night trial, per its site in October 2026.
Prices are set by size and build, so check the king price on the product page rather than the starting price shown for smaller sizes.
Our side by side of the four Wilderness builds covers which suits which sleeper, and the RV mattress buying guide explains foams, weight and trial terms.
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Meet the editorial team and our review standardsRV King Mattress Questions
What size is an RV king mattress?
The most common RV king measures 72 by 80 inches, and both Wilderness RV Mattress and Mattress Insider publish that figure.
That is four inches narrower than a standard king at 76 by 80, which is why a household king rarely fits an RV bedroom.
What is the difference between an RV king and a regular king?
Width is the difference, and length is usually the same.
Wilderness RV Mattress lists an RV King at 72 by 80 inches and a Standard King at 76 by 80, so the household one overhangs by four inches.
What is an RV short king?
It is an RV king with less length, built for rigs where the bed sits against a wall or a slide.
Wilderness lists its RV Short King at 72 by 74.
Mattress Insider gives 72 by 74 or 72 by 75, so measure before you order.
What is an RV narrow king?
It is a king cut two inches narrower to fit tighter bedrooms.
Wilderness calls 70 by 80 an RV Narrow King and 70 by 74 an RV Narrow Short King, while Mattress Insider sells both widths under its RV King name.
Will a regular king mattress fit in my RV?
Only if your platform is at least 76 inches wide, which few RV bedrooms are.
Measure the platform first, because a standard king that is too wide will not sit flat in the frame or crowds the walkway beside it.
Do RV king sheets fit a regular king?
No, and the reverse is also true.
A standard king fitted sheet is cut for 76 inches of width, so it bunches and slips on a 72 inch RV king.
How thick should an RV king mattress be?
As thick as the clearance above the bed allows, and no more.
Wilderness builds its kings at 8 inches and at 10 to 11 inches, so measure the gap under a slide before choosing the deeper one.
Can an RV king mattress fold for a slide out?
Yes, if it is built with a hinge.
Wilderness adds a hinge so the foot of the mattress flips up when a slide comes in, and it also cuts rounded corners and notches to match the platform.
Keep Sizing the Bed
Sizing a Queen Bed Instead
The short queen and RV queen sizes, and where they differ.
Topper or New Mattress?
Where a topper helps, and where it cannot.
Fitting the New Mattress
Getting a king through the door and onto the platform.
Best RV Mattresses Compared
How four builds differ in depth and feel, and who each suits.