Fitment guide
What size is a sleeper cab mattress?
Short answer: there is no standard size. Truck bunks are oddball dimensions that vary by make, model, and sleeper length — which is why the top search result for this question is a forum thread with two-line answers. Here are the real numbers: the Freightliner OEM part, what working drivers measured in their own bunks, and a five-minute method so you buy the right thing the first time.
Key takeaways
- There is no standard sleeper mattress size. The Freightliner OEM replacement (part 22-75832-002) is 2032 × 990.6 mm — 80 × 39 in — but drivers report bunks from 85 × 42 to 85 × 45 in depending on the truck.
- A mattress that fits a Kenworth may not fit a Cascadia. One driver measured 85 × 42 fitting “nice in my KW700” and “very tight in my Cascadia”, where 85 × 39 fit properly.
- Twin XL toppers (38 × 80 in) are the safe default for lower bunks, but upper bunks are often shorter and narrower — measure both before buying anything.
- Measure the bunk, not the old mattress. Old pads compress, curl, and lie about their dimensions. The pedestal is the truth.
The real numbers
What drivers actually report, by truck
The forum wisdom on this is consistent — and consistently qualified. On TheTruckersReport’s long-running “2013 Freightliner Cascadia 70in sleeper mattress size?” thread, veteran driver peterbilt_2005 put it plainly: “Most bunks have a mattress 85" by 42–45". Its an oddball size. Measure the space you have or stop at a dealer get the sizes for that specific make and model.”
| Truck / source | Reported size | Note |
|---|---|---|
| Freightliner (OEM part 22-75832-002) | 80 × 39 in (2032 × 990.6 mm) | Factory replacement spec; 5 in thick |
| Typical North American lower bunk (driver consensus) | 85 × 42–45 in | “Oddball size” — verify per truck |
| Kenworth T700 (driver report) | 85 × 42 in | Fit “nice” per driver Cranky Yankee |
| Freightliner Cascadia (driver report) | 85 × 39 in | Same 85 × 42 was “very tight” here — width matters more than length |
| Twin XL topper (retail reference) | 80 × 38 in | The safe topper default for lower bunks |
The Cascadia-vs-Kenworth story is the whole lesson: five inches of width is the difference between “fits nice” and “very tight.” Fleet trucks also get re-padded, re-cut, and swapped across units over the years — the mattress in your assigned truck may not be the one it left the factory with. Which brings us to the only method that works.
Sleeper sizes
Sleeper sizes and the upper-bunk trap
The sleeper’s length number — 48, 60, 72 inches on a Cascadia, for example — measures the cab extension, not the mattress. A 72-inch XT Cascadia gives 78 inches between the bunk base and the ceiling, but the lower bunk itself is still an ~80-inch mattress platform. The number tells you headroom and storage, not bedding size.
Two traps to know:
- Upper bunks run smaller. Where fitted, uppers are typically shorter and narrower than the lower bunk, and the ladder side often intrudes. A twin XL topper that fits the lower bunk can overhang the upper.
- Width narrows at the pedestal. Bunk platforms taper around storage boxes and the doghouse. Measure width at the narrowest point — that is your real constraint, not the headline width.
The method
Measure before you buy: the 5-minute method
- Strip the bunk. Bedding and toppers lie; the platform doesn’t.
- Measure length from the head wall to the foot wall, in two places (left and right) — walls are rarely square.
- Measure width at three points — head, middle, foot — and keep the smallest number.
- Measure thickness clearance if buying a full mattress: bunk to ceiling (or upper bunk underside) minus your sleeping height.
- Write down lower AND upper separately. They are different bunks.
Bring those three numbers — length, narrowest width, clearance — and every product below stops being a guess.
Toppers
What this means for mattress toppers
A topper is more forgiving than a mattress: foam trims with a bread knife, and a 1-inch overhang is invisible under bedding. That is why the default recommendation is a twin XL (38 × 80 in) gel topper for lower bunks — it fits the common 80-inch platforms and tolerates the oddball widths. For uppers, measure first and expect to trim. Full scoring and picks live in our sleeper mattress topper guide.
Fitment-safe picks
Two picks that respect fitment
One truck-sized mattress and one forgiving topper — both chosen because their dimensions map to real bunks.
Foamma 5″ × 48″ × 75″ firm bunk mattress — truck/RV sized
15/20 provisional · specs + reviews
A firm foam replacement cut to truck-bunk proportions (48 × 75 in) rather than residential sizes. From our topper and mattress guide — the honest fix when the pad underneath is truly finished.
- Size
- 5 in thick, 48 × 75 in — truck/RV proportions
- Price seen
- about C$404 (as of Sep 2026) at research time, varies
- Fit note
- Slightly long for 80-inch platforms is fine; slightly wide for a 39-inch Cascadia pedestal is not — measure the narrowest width first
Linenspa 2-inch gel memory foam topper — Twin XL
15/20 provisional · specs + reviews
The cheapest fix on the list: 2 inches of gel-infused foam in twin XL that turns a hard-but-intact fleet pad into a sleepable surface, carrying the deepest published review base of any pick here.
- Size
- Twin XL, 38 × 80 in
- Price seen
- about C$45–65 CAD (as of Sep 2026), varies
- Ratings
- about 4.3 stars from more than 127,000 published ratings
- Fit note
- Trims cleanly for narrower bunks and uppers
FAQ
Fitment questions, answered
Is a semi-truck mattress a twin XL?
Close, but not exactly. Twin XL is 38 × 80 in, and many lower bunks accept it — which is why it is the standard recommendation for toppers. But real bunks run 39–45 in wide and up to 85 in long depending on the truck, so treat twin XL as a starting point, not a guarantee.
What size mattress fits a Freightliner Cascadia?
The Freightliner OEM replacement is 80 × 39 in. Drivers report 85 × 39 fitting properly in Cascadias, while 85 × 42 was “very tight.” Width is the binding constraint — measure the narrowest point of your pedestal.
Are upper and lower bunk mattresses the same size?
Usually not. Uppers are commonly shorter and narrower, with ladder and cabinet intrusions. Measure each bunk separately and never assume one measurement covers both.
Can I cut a memory foam topper to fit?
Yes — a bread knife or electric carving knife cuts foam cleanly, and a 1-inch overhang disappears under bedding. This is why toppers are the forgiving option versus full mattresses.
Method
How this guide was made
Research-based. We did not test these hands-on. Scores come from published specs and driver reviews. This guide contains affiliate links to Amazon.ca. As an Amazon Associate I earn from qualifying purchases. By Marcus Reid, September 2026. Municipal rules were checked against the cities’ own bylaw pages in September 2026; bylaws change, so treat the numbers below as a starting point and check the city’s site before a trip.
Keep reading
Related reading
- Best sleeper mattress toppers — full scoring and picks.
- New driver starter kit — the whole cab setup, from day one.
- Buying guide — every scored pick, on one shelf.