Camper van mattresses: the platform decides, not the size chart
Quick answer
Almost every van bed is Trim to fit : foam bought oversized and cut to the platform. Measure wall to wall at the bed height, allow for wheel-well notches, and treat thickness as a headroom decision rather than a comfort one.
Conversions are built around the van's interior, and no two builders leave the same numbers. The bed is usually the last dimension set, after the galley and the garage, so it ends up as whatever rectangle is left — sometimes with a notch cut for a wheel arch.
Measure the platform, including the notches
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.
In a van, add the wall-to-wall measurement at mattress height rather than at floor height: the walls of most cargo vans taper inward as they rise, and a slab cut to the floor width will not drop in higher up.
Thickness and headroom
Every inch of foam is an inch of sitting room lost, and in a fixed-bed layout it is also an inch off the garage below. Dense foam at four to six inches usually beats soft foam at eight.
Condensation under the bed
A van is a metal box that sweats. Foam laid flat on sealed plywood holds that moisture against itself and the underside stays damp. Slats, a spacer mesh or a ventilated base fixes it, and that decision is worth making before the mattress is cut, not after the first damp winter.
Foam sold by the sheet
These are the raw material for a build: rectangles of upholstery foam bought oversized and cut to the platform. None of these products has a manufacturer page behind it, so the dimensions come from the listing — practical to know when you are cutting anyway, since your own measurement is what governs the finished piece.
Trim to fit 24 x 72 x 6 GoTo Foam Upholstery Cushion 44 ILD, 6 in
A firm 44 ILD sheet at six inches thick, 24 by 72. Firm enough to sleep on without a base underneath, which suits a platform build.
Trim to fit 24 x 72 x 6 FoamTouch High Density Upholstery Foam, 6 in
The same nominal 6 x 24 x 72 rectangle at a slightly different density. Two sheets side by side make a 48-inch-wide platform.
Trim to fit 24 x 72 x 4 Foamma High-Density Upholstery Foam, 4 in
Four inches instead of six, for builds where headroom is tighter than comfort. Also useful as a base layer under a thinner comfort sheet.
Ready-made mattresses bought to be cut
A twin XL is 80 inches long and narrow enough to fit most van interiors crosswise. Cutting one down is a normal move, but understand what you are cutting: a covered mattress loses its cover integrity at the cut edge and will need re-covering.
Trim to fit 38 x 80 x 10 EGOHOME Twin XL Memory Foam, 10 in
Ten inches of gel memory foam in twin XL. The most mattress-like starting point on this page, at the cost of headroom.
Measure first 39 x 80 x 8 NapQueen Bamboo Charcoal Twin XL, 8 in
An eight-inch twin XL listed at 39 inches wide rather than the usual 38 — an extra inch that either helps or blocks, depending on your walls.
Airflow underneath
Both of these are underlays that separate foam from a sealed platform so the underside can dry. Neither brand has a website, so the dimensions come from the listing, and both are meant to be cut down anyway.
Trim to fit 59 x 83 Bhyhok Aire-Flow Mattress Underlay
A rolled mesh-fibre mat, roughly 59 by 83 inches, trimmed with scissors to the platform outline.
Trim to fit 59 x 83 GRETJOB Ventilated Underlay Tiles
The same job in interlocking plastic tiles instead of a roll. Easier to fit around a wheel-well notch, since you simply leave tiles out.
Cutting
Template the platform on cardboard first, transfer the outline to the foam, and cut in one continuous pass with a long blade against a clamped straight edge. Leave a small allowance at the wheel-well notch: it is easier to shave foam twice than to fill a gap.
Questions people ask
What size mattress fits a camper van?
Whatever the platform is. Conversion beds are built to the van's interior width, so a common build lands near 48 by 72 inches, but the number comes from the build, not from a size chart.
Can a mattress lie sideways across a van?
In a high-roof cargo van the interior width between the walls decides it. Sleeping crosswise saves floor length for the galley but caps how tall the sleeper can be, so measure the wall-to-wall distance before committing the layout.
What thickness works on a van platform?
Thin enough to keep sitting headroom and to let the garage space underneath stay usable. Four to six inches of dense foam is the common range in builds where the bed sits high.
Does a van mattress need airflow underneath?
Yes. Foam laid directly on a solid plywood platform in a van traps moisture from condensation. Slats, spacer matting or drilled ventilation under the foam is standard practice in conversions.
Sources
- Manufacturer specification pages for each product named, checked on the brand's own site
Last checked 2026-08-03