If you have ever woken up in a travel trailer with a sore hip and a stiff back, you already know the problem. Factory RV mattresses are thin, firm, and built to a price. The good news is that a memory foam topper fixes most of that, and the only real decision you need to make is how thick it should be. We cut RV toppers in 2 inch, 3 inch, and 4 inch thicknesses in our Phoenix, AZ factory, and we get this question every single day. Here is how we answer it.
The short answer
For most RV owners, a 3 inch gel memory foam topper is the sweet spot. It adds enough foam to cushion your shoulders and hips on a firm factory mattress without making the bed so tall that sheets stop fitting or the slide-out will not close. If your mattress is only slightly too firm, or you are outfitting a bunk with limited headroom, go 2 inches. If your mattress is truly worn out and you are trying to rescue it rather than replace it, go 4 inches.
What each thickness actually does
2 inch: a subtle upgrade
Two inches of gel memory foam softens the surface of a firm mattress without changing its overall feel. You still get the support of the mattress underneath, with a layer of pressure relief on top. It is the right pick when:
- Your RV mattress is fairly new and just a little too firm
- You are a back or stomach sleeper who likes a supportive feel
- You are fitting a bunk, a cab-over bed, or a bed under low cabinets
- You have a slide-out or a bed platform that lifts for storage and cannot spare the height
3 inch: the most popular choice
Three inches is the thickness we sell more of than any other, and for good reason. It is enough foam for a side sleeper’s shoulder to sink in and settle, enough to smooth over a mattress that has started to feel lumpy, and still manageable in a short queen or RV king. Choose 3 inches when:
- You sleep on your side or switch positions during the night
- Your mattress is a few years old and has lost some comfort
- Two people share the bed and you want less motion transfer
- You want the biggest comfort change for the least added height
4 inch: maximum pressure relief
Four inches is a lot of memory foam. It gives deep contouring and a noticeably softer, more plush feel, and it can make a thin or sagging mattress usable again. It is best when:
- You have joint pain, hip pain, or shoulder pain and want the softest possible surface
- You weigh more than average and find 3 inches bottoms out
- Your RV mattress is thin (5 inches or less) or noticeably worn
- You have plenty of clearance and deep-pocket sheets
A quick comparison
| Thickness | Feel | Best for | Watch out for |
|---|---|---|---|
| 2 inch | Light cushioning, mattress still does the work | Firm but decent mattresses, bunks, back sleepers | May not be enough for side sleepers |
| 3 inch | Balanced softness and support | Most sleepers, most RV beds | Check sheet pocket depth |
| 4 inch | Deep, plush contouring | Worn mattresses, joint pain, heavier sleepers | Height, slide-out clearance, warmer feel |
Four things to check before you decide
1. Your mattress condition
A topper adds comfort, but it cannot create support that is not there. If your mattress is thin but flat and firm, any thickness will work well. If it has a visible dip or a broken-down spot, a thicker topper (3 or 4 inches) will hide it better, but you might also want to read our guide on how to fix a sagging RV mattress, which covers adding a firm base layer underneath.
2. Your sleep position and weight
Side sleepers put a lot of weight on a small area, so they benefit from more foam. Back and stomach sleepers generally do better with less. Heavier sleepers press further into memory foam, so they often need the next thickness up from what a lighter person would choose.
3. Clearance
Measure the space above your mattress. RV bunks, cab-over beds, and beds tucked under cabinets often have less than 30 inches of headroom. Slide-outs need to close over the bed. Beds with lift-up storage need to clear the frame. If height is tight, 2 inches is the safe choice.
4. Sheets
A 6 inch RV mattress plus a 3 inch topper is a 9 inch bed, which most standard sheets handle fine. A 4 inch topper on an 8 inch mattress may need deep-pocket sheets. Our covered RV Mattress Topper 2.0 has built-in straps that fit mattresses from 6 to 16 inches tall, which keeps everything in place even when the bed is used as a couch during the day.
Does thickness change how warm it sleeps?
A little. More memory foam means more material hugging your body, which can hold more heat. Our foam is gel-infused and open-cell, so it breathes better than older memory foam, and most customers sleep cooler than they expected even on a 4 inch topper. If you run hot and are on the fence, choose 3 inches rather than 4.
Get the size right too
Thickness is only half the fit. RV beds come in odd sizes, and a topper that is a few inches too long bunches up against the wall. Measure your mattress and match it to our RV mattress sizes chart. We stock 12 RV sizes, including short queen, RV king, short king, three quarter, and six bunk sizes, and we can cut any other rectangle up to 80 by 84 inches through our custom topper program.
Still not sure?
When in doubt, choose 3 inches. It works for the widest range of people and beds, and every LOUNJ topper is backed by our 30-Night Happiness Guarantee, so if it is not right you can send it back free and try another thickness. Browse our RV mattress toppers, made in Phoenix, AZ, CertiPUR-US certified, and shipped free to the lower 48.