How to Measure an RV Mattress Before You Buy

On this page (14 sections)

1. Why measure the platform instead of the old mattress
2. What you need before you start
3. How to measure an RV mattress step by step
4. Check whether the bed is square
5. How to read a mattress size line
6. Compare your numbers with common sizes
7. What to do if your numbers fall between sizes
8. Pop-up beds need two measurements
9. How to tell the numbers are right
10. Sheets and protectors need the same numbers
11. Notes for bunk beds
12. Mistakes that lead to the wrong order
13. Write your numbers down
14. Start measuring, then shop by the numbers

Here's how to measure an RV mattress space with a tape measure, a notepad and a helper to hold the far end. RV beds rarely match home sizes, and a 1 inch miss can leave a gap at the foot or a mattress that won't sit flat.

RV mattress sizes are not standard, so a name like short queen can mean slightly different numbers from one maker to the next. Your tape measure settles the question faster than any size name does.

Why measure the platform instead of the old mattress

The platform is the space the new mattress has to fill, so its numbers matter more than the old mattress's numbers. An old mattress may have shifted or sagged over time, which makes its size hard to trust.

If the old mattress is still on the bed, measure the platform edges you can reach, then confirm the numbers once the bed is clear. Measuring the platform also shows any lip, rail or cabinet edge the new mattress must sit beside.

If a board or panel covers the platform, measure to the edge of that panel. The panel is the surface the mattress actually sits on.

What you need before you start

You need a tape measure, a pencil, a notepad and a second person for longer runs. That is enough for most RV beds, and no special tools are required.

Craftsman rates its 25-foot tape at plus or minus 1/16 inch per 10 feet, which is plenty of precision for a bed. Fractions are printed on the blade, so a half or quarter inch is easy to read without guessing.

Write each reading as you take it, so a misread number does not carry into your card.

How to measure an RV mattress step by step

Work through the steps in order, and write down each number as you go. The numbers you collect become the card you use to compare mattresses.

Step 1: Measure the width at the head and foot

Measure the width from one edge of the platform to the other, first at the head and then at the foot. Write both numbers down, because an older bed can be a little narrower at one end.

If the two numbers differ, use the smaller one when you compare sizes. The mattress has to fit the narrower end, so a wider size will not fit.

Measure once more at the middle. If the middle reads differently, note it, since it can point to a bowed frame.

Measure to the outside edge of the platform, not to a cabinet, wall or rail. A rail or bumper can take up space the mattress needs.

Step 2: Measure the length down the middle

Measure the length from the head edge to the foot edge, running the tape down the center of the bed. Then check each side, and write both numbers down if they differ.

Length is the number that varies most between short queens. A 74-inch bed and a 75-inch bed both count.

That one inch decides which sheets and protectors fit. Short queen mattress dimensions compares 74 and 75 in detail.

Step 3: Check the corners and any cut

Check each corner for a square, a rounded radius or a cut. Note each one on your card, because the corner shape decides whether a standard mattress sits flat.

A rounded corner can leave a square mattress sitting slightly off the platform. Note where the curve starts along each edge, so you can judge the fit.

A cut corner is an angled or curved edge that removes one corner of the mattress. Measure the length of the angled edge and the distance across the cut at each end, then note which corner is missing.

Stand at the foot of the bed and look toward the head to name the side. Left and right cuts are not interchangeable, so label the side on your card before you order.

ZAQYCM builds angled bunk mattresses to the numbers you send, along with a photo and your choice of left or right cut. Hand measurements can run 1 to 3 cm off, and a custom mattress shouldn't be trimmed after delivery, so measure twice and get the numbers right the first time.

Step 4: Measure the height and clearance for the mattress

Measure from the platform up to the lowest cabinet, ceiling or slide-out edge, with the slide pushed in. That number is the room the mattress and any topper have to fit into.

A thick mattress is most likely to clash with a slide-out, so measure that spot twice. Check the space with the slide in and out if the bed sits near one.

Add the bed frame, foundation or base height to the mattress height. Use that total, not the mattress height alone, to judge how tall the finished bed will be.

Step 5: Check the weight for a lift bed

If your bed lifts on struts, check the mattress weight against the lift's rating before you order. A heavier mattress puts more load on the struts every time the bed moves.

Weights in this guide range from about 15.5 pounds for a 6-inch foam bunk to 70 pounds for a 10-inch hybrid full. Look up the lift's rated capacity in your RV manual, and add any topper's weight to the mattress weight.

Step 6: Plan the delivery route

Many RV mattresses arrive compressed, rolled or vacuum-sealed in a box. Measure the narrowest doorway, hallway and slide-out path on the route before the box arrives.

Expansion times run from a few hours to 72 hours, so plan for the bed to take a day or more to reach full height.

Check whether the bed is square

Measure from one head corner to the opposite foot corner, then measure the other diagonal. If both diagonals match, the platform is close to square, and a rectangular mattress will sit evenly.

If the diagonals differ by more than a little, the platform is out of square. Note the difference on your card, because a mattress may sit crooked or leave a gap at one corner.

Diagonals are easiest with two people. Hold the tape at the same point on each corner, and read the numbers without moving the tape.

How to read a mattress size line

Sizes are often written width first, such as 60 x 75, while spec tables write length first. The Zinus short queen, for example, is 74 inches long, 60 inches wide and 8 inches thick.

The EGOHOME RV king follows the same pattern: 80 by 72 by 10 inches means 80 inches long, 72 inches wide and 10 inches thick. Read the L, W and Th letters, not only the order in the title, before you compare it with your card.

If a mattress shows only a size name, find its dimensions in inches before you order. Compare length to length and width to width, so a 60 by 75 mattress is not mistaken for a 75-inch-wide bed.

Compare your numbers with common sizes

Match your width and length to the mattress dimensions first, then check thickness against your clearance. The table shows common matches, but the exact inches decide the fit.

Dimensions describe the mattress, not your platform. A 60 by 74 mattress needs a platform at least that large.

Common matches are typical, so confirm every size against your own numbers before you order.

If your width reads about 53 or 60 inches, our short queen vs RV full comparison shows how those two beds differ.

What to do if your numbers fall between sizes

Sometimes a platform reads between two standard sizes, such as 74.5 inches. Choose the mattress that is equal to or slightly smaller than your platform, never a larger one.

A slightly smaller mattress may need a snug sheet to stay in place, so check the sheet label and depth before you order. If the gap is more than an inch in either direction, measure again, since a second measurement often catches a mistake.

When your length sits between a short queen and a standard queen, short queen vs queen works through the choice with a worked example.

Pop-up beds need two measurements

A pop-up bed end has two sizes that matter: the width and length with the roof up, and the room left when the roof is closed. Measure the bed end with the roof up, then check the closed clearance, because the mattress must fold with the roof.

Ends vary in size, and some are only 48 inches wide, so do not assume a queen end. Thin foam is the usual choice for these beds, and best pop-up camper mattresses lists options by size.

How to tell the numbers are right

Take each reading twice, and ask a second person to read the tape while you hold the end. If two readings differ, measure a third time before you write the number down.

Then compare your card with the bed as a whole. Width, length and depth should all agree with the mattress you plan to buy, not just the size name on the box.

Take a photo of the bed with the tape across it, so you can check a reading later without going back to the room.

Sheets and protectors need the same numbers

Sheets and protectors are labeled by width, length and depth, so match all three to your measurements. A length that is a single inch off can change which product fits.

A short queen sheet is cut for a 75-inch bed and won't suit a regular queen, so check the label before you order.

Waterproof protectors follow the same sizing. The Kingnex has a waterproof membrane on the back and is machine washable in cold water, then tumble dried on low heat.

Notes for bunk beds

Bunk beds have their own limits, so a standard mattress guide is only a starting point. Start with the maximum mattress thickness and guardrail guidance from the bunk maker, since that limit comes before any general rule.

A thicker top-bunk mattress raises the sleeper closer to the guardrail, so the bunk maker's maximum thickness matters most there. The Consumer Product Safety Commission publishes general bed and bunk safety information, which is worth reading before you order a replacement.

Measure the usable space inside the bunk too, since rails and a ladder can reduce it.

If your bunk has a cut corner, our corner-cut RV bunk mattress picks compare six replacements by size and cut.

Mistakes that lead to the wrong order

Rounding 74 up to 75

A 75-inch mattress can look close enough when your bed reads 74. Use the number you measured and check the mattress length against it, not a rounded guess.

Forgetting the topper

A topper adds height, so a mattress that clears a cabinet alone may not clear it with a topper on top. Measure with the topper in place, or add its thickness to the mattress number.

Trusting the size name alone

Names like short queen and RV king are not standard. The Zinus short queen is 74 inches long, while the Grbsy short queen and the Coldwind sheet are 75.

Buying before measuring the door

A mattress that fits the bed can still fail at the door. Measure the route before you order, and remember the weight when you plan the move.

Write your numbers down

Keep one card with every measurement, so you can compare each mattress without measuring again. Take the card with you when you shop.

• Width at the head of the bed
• Width at the foot of the bed
• Length down the middle
• Length on each side, if they differ
• Corner shape: square, rounded or cut
• Cut edge length and which corner is cut
• Height under cabinets with the slide pushed in
• Platform or base height
• Lift rating, if you have a lift bed
• Narrowest doorway on the delivery route
• Depth of the sheet or protector you plan to buy

Read the card line by line before you place an order.

Start measuring, then shop by the numbers

Pick the size your measurements match. A mattress larger than your platform will not fit, so do not round up.

If your numbers fall between two sizes, measure again at the head and foot before you choose. When the numbers are set, RV mattress sizes lists every size family in one chart.

Frequently asked questions

How do I measure an RV mattress?

Measure the bed platform, not the old mattress, taking the width at the head and foot and the length down the middle. Then check the corners for rounding or cuts, and measure the height under any cabinets with the slide-out pushed in.

Should I measure the width at the head or the foot?

Measure both, and use the smaller number when you compare sizes, because the mattress has to fit the narrower end of the platform. Write down both numbers, then measure once more at the middle to check for an uneven frame before you order.

How do I measure a corner cut on an RV bunk?

Measure the angled edge and the distance across the cut at each end, then name the cut corner by standing at the foot of the bed and looking toward the head. Measure twice, since ZAQYCM warns that hand measurements can run 1 to 3 cm off.

Do I need to measure the height under cabinets?

Yes, if you plan to use a thick mattress or a topper, because the space above the bed sets the limit. Measure from the platform to the lowest cabinet or slide-out with the slide pushed in, and add the bed frame or base height to the mattress height.