RV king, 72 x 80 — four inches narrower than the bed you have at home
Quick answer
An RV king is about 72 x 80 — four inches narrower than a residential king at 76 x 80. That makes a house king a Won't fit 76 x 80 in this cavity, and it makes the RV size Trim to fit in practice, because so little is made in it that trimming a wider mattress is a normal path.
Width is what matters here, and width is exactly what the slide-out mechanism cares about. The four inches that separate the two king sizes sit in the travel path of the bedroom slide, which is why an over-wide mattress in this bed does not merely overhang — it stops the coach closing.
The sizes it gets confused with
| Size | Nominal W x L | Fit class | What that means |
|---|---|---|---|
| RV Queen | 60 x 80 in | Drop-in | Identical to a residential queen. Confirm before assuming yours is short. |
| RV Short King | 72 x 75 in | Measure first | Rare. Usually needs two twin-size pieces or ordered foam. |
| RV King | 72 x 80 in | Trim to fit | Four inches narrower than a residential king (76 x 80). A residential king will not close the slide. |
| RV California King | 72 x 84 in | Measure first | Matches residential Cal King width and length in most coaches. |
Measure the sleeping platform itself — corner to corner, inside any side rails — not the old mattress, which may have compressed or been trimmed by a previous owner. Write down width, length and the height you have under a slide-out or overhead cabinet. Order to the platform.
Why the search results look empty
Checking this size across the marketplace turned up a pattern worth stating plainly: almost everything sold as "RV king" is bedding rather than a bed. Sheets, protectors and toppers in 72 x 80 are plentiful; full mattresses in that size are close to absent, and the ones that exist come from small makers rather than the bed-in-a-box names. If you have been searching and finding nothing, the market is the problem, not your search terms.
What is available
Trim to fit 72 x 80 x 10 Custom Classic Gel 10, RV King
Ten inches of gel-infused memory foam cut to the RV king footprint, from a maker that publishes the 72 x 80 size on its own site. Effectively the only full mattress in this size on the marketplace at the time of checking.
Trim to fit 72 x 80 x 2 CRAURU RV Topper, 2 in
A two-inch topper listed for bunks but stated at 72 x 80, which is an RV king rather than any bunk. Useful over an existing king platform; the naming mismatch is the listing's, and no maker page confirms the size.
Two products is not a shortlist anyone would choose to publish. It is what the size actually offers, and saying so is more useful than padding the page with residential kings that will not close your slide. The checking procedure is on how we test.
If nothing here fits
The fallback in this size is foam cut to the platform: a sheet ordered oversized and trimmed, covered separately. That route is described on the van page, where cut-to-fit is the norm rather than the exception, and the same blades and technique apply in a coach.
Questions people ask
What size is an RV king mattress?
About 72 by 80 inches. A residential king is 76 by 80, so the RV version is four inches narrower while the length matches.
Can I put a residential king in an RV?
Only where the platform actually measures 76 inches wide, which is rare. Those four extra inches sit where the bedroom slide travels, and the mattress will stop the slide from retracting.
Why are RV king mattresses so hard to find?
Because the size is small enough to be RV-only and large enough to be expensive to ship. Searches for this size return mostly toppers, sheets and protectors rather than mattresses, which is a fair summary of what the market offers.
What is a short king?
72 by 75 — the same width as an RV king with five inches less length. It is rarer still, and usually ends up as two twin-size pieces or ordered foam.
Can two twin XL mattresses make an RV king?
Two twin XL pieces give 76 by 80, which is a residential king rather than an RV king, so the pair is too wide for most coaches. Cutting them down works, but you lose the finished edge on the cut side.
Sources
- Manufacturer specification pages for each product named, checked on the brand's own site
Last checked 2026-08-06