How to Order a Custom Size Foam Mattress for an RV, Boat or Daybed

Updated November 2026 · By Sam K, Fabrica Kraft

Quick answer: To order a custom size foam mattress, measure the bed platform (not the old mattress) for width and length, note any clipped or rounded corners, and choose a thickness: 4 to 6 inches for bunks, daybeds and trundles, 6 to 8 inches for a main bed. Common RV sizes include the short queen (60 × 74–75 in) and RV king (72 × 80 in), but RV and boat beds vary, so always measure your own.

Standard mattresses are made for standard bedrooms. RVs, campers, boats, daybeds and antique frames are not. A mattress that is an inch or two too big won't sit flat; one that is too small leaves a gap that pillows fall into. A foam mattress cut to your exact size fixes both.

Common RV and odd mattress sizes

These are typical sizes, width × length in inches. Manufacturers vary, so treat them as a starting point, not a substitute for measuring.

Note that an RV short queen is about 5 inches shorter than a regular 60 × 80 queen, and an RV king is narrower than a standard 76 × 80 king. That is why a standard mattress often won't fit.

How to measure for a custom mattress

1. Measure the platform, not the old mattress. Old foam sags and spreads, so its size is no longer accurate. Measure the inside of the frame or the platform the mattress sits on.
2. Width and length: measure at both ends and in the middle. If the numbers differ, use the smallest so the mattress fits without bowing.
3. Corners: RV beds often have clipped or rounded corners at the foot so you can walk past. Measure how far each corner is cut back on both sides, or trace it onto paper.
4. Odd shapes: for boat V-berths, dinette beds and anything angled or curved, make a full-size paper template of the platform and mark which side is the top.
5. Height limits: check how much space you have under cabinets, windows or a bunk above, so a thicker mattress doesn't crowd the space.

For a deeper walk-through on templates, see how to make a cushion template. For RV dinettes, see our RV dinette cushions guide.

How thick should a custom foam mattress be?

• 4 to 6 inches: bunks, daybeds, trundles and fold-out dinette beds.
• 6 to 8 inches: a main bed you sleep on every night.

We cut foam up to 6 inches thick from one solid piece, and from over 6 to 8 inches we glue two layers of the same foam together. For anything thicker, contact us for a quote.

Choosing the foam

• High Density: a medium feel that suits most sleepers.
• Luxury: firmer, for people who prefer a firm bed.
• Dry Fast: open-cell foam that lets water drain through, for boat berths and beds that can get damp.
• Dacron wrap (optional): a 1-inch layer of polyester fiberfill around the foam for a softer top and rounder edges.

Foam only, or a finished mattress?

• Foam only: if you have a cover you like, or want to use a fitted sheet, order a custom size foam mattress.
• Foam and cover: for a finished, zippered mattress, see the custom boat mattress or daybed cushions, or add a custom cover.

Every piece is cut to within ¼″ (maximum ±1″) of your measurements, and most orders ship in 2–3 weeks.

Frequently asked questions

Can I use a regular queen mattress in an RV?

Sometimes, but many RVs use a short queen that is about 5 inches shorter than a regular queen. Measure the platform first; a mattress that is too long will hang over or block the bedroom door.

Can you cut a mattress with rounded corners?

Yes. Send the measurements of each corner, or a paper template, and we cut the foam to match.

What is the best mattress for a boat V-berth?

A foam mattress cut from a template of the berth, in Dry Fast foam if the cabin gets damp, so water drains through instead of soaking in.

Can a V-berth mattress be split into two pieces?

Yes. The boat mattress with center cut is split down the middle so each half lifts on its own for the storage below.

Sources

• Sleep Foundation: RV mattress sizes