King RV Mattress Dimensions: What "King" Actually Measures
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A reader shopping for a "King" RV mattress will find two different footprints sold under names that both contain the word "King" — and, from at least one manufacturer, under names that differ only by whether "RV" is in the title. This page covers the published width and length for "RV King" (72×80), the competing "King"/"Narrow King" usage at 76×80, where "Short King" (72×75) fits in as a separate class, and what to measure before you order.
It does not cover full mattress-replacement steps — see replacing an RV mattress step by step for that — firmness or comfort comparisons, or the other RV size classes in detail (short queen, queen, bunk each have their own page).
Quick Answer
| Name you'll see on a listing | Width | Length | Source |
|---|---|---|---|
| "RV King" (majority usage among RV-specific mattress sellers) | 72 in | 80 in | The Big Rig Mattress, RV King 72×80 product listing |
| "King" (same footprint as a residential king; one manufacturer's guide calls the 72×80 version "Narrow King" instead) | 76 in | 80 in | Lippert Components, "Your Comprehensive Guide to RV Mattress Sizes" |
These two rows are not two different beds you can ignore because one has "RV" in the name and the other doesn't — the next section shows why the same seller sometimes lists both.
Why "King" Doesn't Mean One Measurement
The clearest proof of this isn't two unrelated brands disagreeing — it's one brand's own catalog. WanderRest's "Cool Hybrid 10˝" RV mattress line sells an "RV King 72×80" and a plain "King 76×80": same brand, same construction, same "Medium" firmness word, four inches of width apart. A shopper who orders by the word "King" alone, without checking the stated number, has a one-in-two chance of landing on the wrong footprint from the exact same seller.
Lippert Components, an RV equipment manufacturer, independently publishes the same split under different terms: its sizing guide reserves "RV King" for the full 76×80 residential footprint and calls the 72×80 version a "Narrow King" instead. The language differs from what most RV-specific mattress sellers use, but the underlying conflict — two footprints, overlapping names — is the same one WanderRest's own catalog shows directly.
A 76×80 mattress will not fit a sleeping platform or frame built for a 72-inch-wide RV King footprint. Four inches is not a rounding error in a fixed RV bed surround — it's the difference between a mattress that sits flush and one that overhangs the frame on both sides.
Which Figure Applies to Your RV
Match the number on your own platform, not the name on the listing:
- Sleeping platform or frame around 72 inches wide → the listing should state 72×80, whatever it's titled.
- Platform around 76 inches wide (less common in RVs, closer to residential) → 76×80, whatever the listing calls it.
- Platform shorter than 80 inches in length, around 72×75 → that's a length problem, not a width one — see Short King below.
For the full chart covering every RV mattress size class, not just King, see our full RV mattress size chart.
Short King Is a Different Size, Not a Typo for RV King
"Short King" is five inches shorter than "RV King" at the same 72-inch width — 72×75 rather than 72×80, per the retailer listings checked for this page (INEHM and a comparable Therapedic listing). That's a genuinely different, smaller class, not a misprint of "RV King."
One caveat on sourcing: unlike the 72×80 and 76×80 figures above, which are corroborated across multiple RV-specific sellers and an equipment manufacturer's guide, "Short King" at 72×75 is sourced only to the specific listings checked for this page — no second independent RV mattress manufacturer publishes it as a named market-wide class at the time of writing. Treat it as what these listings state, not as an established standard the way "RV King" and "King" are.
The mix-up risk is real: at least one seller (Therapedic) titles a 72×75 mattress "RV King" — the same name used elsewhere for a 72×80 bed. A reader matching on name alone can land on a mattress that's five inches short, not just a different brand. See Short King RV mattress picks for options sized to this class specifically.
RV mattress size classes at a glance
RV mattress size names — short queen, queen, king, bunk — sound like residential mattress names, but no standards body sets what they measure, and RV mattress sellers do not all agree with each other. This table compiles the width and length each size class is given by RV-specific mattress manufacturers and retailers, states where each size typically appears, and names it plainly where two sources use the same size name for two different measurements. A blank or "not standardized" entry means the market has not converged on a figure for that class — most often true for cab-over and corner-cut beds, which are shapes, not just two numbers.
| Size class | Width (as published) | Length (as published) | Where it's typically used | Source | Source checked |
|---|---|---|---|---|---|
| Short Queen | 60 in | 75 in | The most common queen-size bed in travel trailers and fifth wheels — shortened from a residential queen to clear wheel wells, slide mechanisms, or aisle space. | Lippert Components, "Your Comprehensive Guide to RV Mattress Sizes" (RV equipment manufacturer) | 2026-10-12 |
| Queen (RV) | 60 in | 80 in | Full-length queen used where the bedroom has enough length to skip the short-queen cut — larger travel trailers, fifth wheels, and Class A bedrooms. Same footprint as a residential queen. | Lippert Components, "Your Comprehensive Guide to RV Mattress Sizes" (RV equipment manufacturer) | 2026-10-12 |
| King (RV) | 72 in | 80 in | Larger fifth wheels and Class A motorhomes with wider bedroom layouts. | The Big Rig Mattress, RV King 72in x 80in product listing (RV mattress manufacturer) | 2026-10-12 |
| Cab-over / Custom | Not standardized — no published range | Not standardized — no published range | Cab-over sleeping areas, corner-cut and notched platforms, and any bed shape that isn't a plain rectangle. These go straight to measuring; there is no size-class table to check against. | Camp Addict, "A Cut Corner RV Mattress CAN Easily Be Replaced!" (consumer RV publication) | 2026-10-12 |
How these numbers were produced: Each width and length is the figure stated by the cited source for that size class, not derived or calculated. Where a size class had no single published figure across the sources checked (Bunk, Cab-over/Custom), the range or absence is reported as found rather than resolved into one number. Where two sources used the same size-class name for different dimensions (King), both figures are reported and the conflict is named in the caveats rather than silently resolved by picking one as correct.
- A width or length marked "not standardized" means no source publishes a single figure for that class — not that none was looked for. No number on this table is estimated, averaged, or carried over from a similar size class.
- The name "King" does not point to one measurement across the market. Three independently checked RV mattress sellers (The Big Rig Mattress, Adventure RV Mattress, and Beloit Mattress Company) all describe a 72 in by 80 in mattress as "RV King." A separate RV equipment manufacturer's published guide instead reserves "RV King" for a 76 in by 80 in mattress — the same footprint as a residential king — and calls the 72 in by 80 in version a "Narrow King." This table reports the 72 in by 80 in figure because it is the usage the majority of checked RV-specific mattress sellers use, but the naming conflict itself is a reason to measure before ordering by name alone.
- "Bunk" is reported as a range, not a single figure, because the sources checked list half a dozen different bunk measurements without identifying any one of them as standard. A bunk's actual size is set by the frame built into that specific floorplan, not by a shared bunk standard.
- Cab-over, corner-cut, and notched beds have no published size range because the shape itself varies by floorplan — a width-and-length pair can't describe a shape with an angle or notch cut into it. Several manufacturers build custom mattresses to a reader-supplied sketch and measurements for exactly this reason.
- Every figure above is a published range, not a measurement of any individual reader's bed. RV mattress sizes vary by manufacturer and model year even within the same named class; measure the existing mattress or the sleeping platform directly before ordering a replacement.
These are the entries that matter for this guide. The full table, with every row and its source, is in our RV Mattress Dimensions: Every Standard Size, Explained.
How to Measure Before You Order
- Measure the existing mattress at its widest and longest point — not the frame rails. RV frames often run slightly larger than the mattress that originally shipped with the rig.
- If there's no mattress to reference (a removed or already-discarded bed), measure the sleeping platform itself.
- Check for slide-out encroachment, wall taper, or cab-over notches. A flat width-by-length figure won't show any of these — that's a shape problem, and cab-over and custom-shape beds go straight to measuring rather than a size-class table.
- Re-measure after removing the old mattress. Foam compresses over years of use and can read narrower than the platform underneath actually is.
Mattresses That Show This in Practice
These aren't ranked picks — for a ranked list of king-size options, see best king RV mattresses. They're the same three dimension classes discussed above, shown as real listings.
The WanderRest Cool Hybrid 10" RV Mattress in RV King 72×80, Medium, is the 72×80 example — the majority-usage "RV King" figure from the Quick Answer table above.
The WanderRest Cool Hybrid 10" RV Mattress in King 76×80, Medium, is the same line, same firmness, same construction as the pick above — just without "RV" in the name, and four inches wider. It's the concrete, same-manufacturer example of the naming gap this page is built on.
The INEHM Short King Mattress, 8 Inch, at 72×75 is the Short King example — correctly named for its own footprint, not a mislabeled "RV King."
Common Mistakes
Ordering by the word "King" alone. The name doesn't settle the footprint — the WanderRest pair above proves it inside one catalog. Check the stated width and length every time, not just the size-class name.
Assuming "Short King" and "RV King" are the same thing because they share a word. They're five inches apart in length at the same width. A listing titled "RV King" at 72×75 (see the Therapedic example above) is a Short King wearing the more common name.
Measuring the mattress currently on the bed instead of the platform. Foam compresses over years of use. A mattress that's been in place for a while can read narrower than the sleeping platform actually is — measure the platform itself when you can.
FAQ
What size is a king RV mattress?
Most RV-specific mattress sellers publish "RV King" at 72 inches wide by 80 inches long. At least one RV equipment manufacturer's guide instead uses "King" for a 76×80 bed and reserves a different term, "Narrow King," for the 72×80 size — so the word "King" alone doesn't settle which figure applies to a given listing.
How do you measure a king RV mattress?
Measure the existing mattress at its widest and longest point, not the frame rails, and re-measure after removing an old mattress since foam compresses over time. See How to Measure Before You Order above for the full checklist, including slide-out and cab-over checks.
Is RV King the same size as a regular king mattress?
No. A residential king mattress is 76×80 — the same footprint one manufacturer's guide calls "King" in the RV context. The majority "RV King" usage among RV-specific sellers is 72×80, four inches narrower. See RV King vs. regular King, compared for the full comparison.
What's the difference between Short King and RV King?
Five inches of length at the same 72-inch width: Short King is 72×75, RV King is 72×80. They share a word and a width, which is exactly why listings and shoppers conflate them.
Will a 76×80 mattress fit a bed built for a 72-inch RV King?
No. A fixed RV bed surround doesn't flex to absorb four inches of extra width the way a residential bed frame might. Measure your platform before ordering either size.
Why do two RV King mattresses from the same brand have different sizes?
They don't, technically — one of the two isn't labeled "RV King" at all. WanderRest's "Cool Hybrid 10˝" line sells an "RV King 72×80" and a plain "King 76×80" in the same line, same firmness; the size difference tracks the name difference exactly.
Sources Reviewed
Figures compiled from RV-specific mattress manufacturer and retailer listings and one RV equipment manufacturer's published guide: The Big Rig Mattress (RV King 72×80 product listing), Lippert Components ("Your Comprehensive Guide to RV Mattress Sizes," the source for the 76×80 "King"/"Narrow King" figures), and the INEHM and Therapedic listings for the 72×75 Short King figure. WanderRest's own RV King 72×80 and King 76×80 listings, re-checked against Amazon during fact-check, corroborate the two majority-usage figures. All checked on the dates shown in the underlying dataset. No figure here is estimated or averaged from a similar size class.
Related Guides
- Full RV mattress size chart, all classes
- Best king RV mattresses
- RV King vs. regular King, compared
- Short King RV mattress picks
- Queen RV mattress dimensions
- King RV mattress toppers