The Complete Guide to Odd-Size & Custom Mattresses
Every non-standard mattress size explained — from someone who's recycled over 1.15 million mattresses, including thousands of odd sizes that were used way past their lifespan.
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The Odd-Size Mattress Problem Nobody Talks About
About 5% of the mattresses I remove are odd sizes — RV mattresses, semi-truck sleepers, antique beds, boat mattresses, oversized kings, and everything in between.
They're almost always in terrible condition.
Not because the owners don't care. But because they have no idea where to buy a replacement.
When you need a standard Queen mattress, you have hundreds of options. Walk into any mattress store, browse any website, and you'll find exactly what you need in 10 minutes.
But when you need a 60×75 RV Short Queen? A 42×80 semi-truck sleeper? A mattress for your grandmother's antique bed frame? Good luck.
Most people end up in one of two situations:
- They keep sleeping on a mattress that should have been replaced years ago. I've removed odd-size mattresses that were 10, 15, even 20 years old — sagging, body impressions permanent, foam completely broken down. The owners knew it was bad. They just didn't know where to find a replacement.
- They buy the cheapest thing they can find online. Usually from an RV parts site or discount retailer. A thin piece of low-density foam that feels okay for six months, then falls apart.
Here's What Most People Don't Know
Quality odd-size mattresses exist. The same manufacturers who make the mattresses in your home — with proper foam densities, quality spring units, durable construction — also make them in custom and non-standard sizes. You just have to know where to look. That's what this guide is for.
Why Odd-Size Mattress Owners Get Stuck
The mattress industry is built around six standard sizes:
| Size | Dimensions | Notes |
|---|---|---|
| Twin | 38" × 75" | Most common single size |
| Twin XL | 38" × 80" | 5" longer, college dorms |
| Full / Double | 54" × 75" | Traditional couples size |
| Queen | 60" × 80" | Most popular size today |
| King | 76" × 80" | Widest standard size |
| California King | 72" × 84" | Longest standard size |
Everything else — every RV, boat, truck, antique bed, or oversized frame — falls outside this system. That creates problems:
- Retail stores don't stock them. Walk into Mattress Firm or any local store and ask for an RV Short Queen. They won't have it. Most won't even know what you're talking about.
- Online options are mostly junk. Search "RV mattress" and you'll find pages of cheap foam slabs from RV parts retailers. They're thin, low-density, and designed to hit a price point — not to actually be comfortable or last.
- Quality options are hidden. Good manufacturers DO make odd-size mattresses. But they don't advertise them. You have to know where to look, what to ask for, and what to avoid.
- People give up. After an hour of frustrating searching, most people either keep their old mattress or buy the cheapest option just to be done with it.
What I See Every Week
Odd-size mattresses that have been slept on for 10-15 years past their lifespan because the owner didn't know they had better options. The foam is completely broken down, there are permanent body impressions, and sometimes the cover is literally disintegrating. These aren't careless people — they're stuck people.
RV & Camper Mattresses
RV mattresses are the most common odd-size mattresses I remove — and they're almost always in rough shape.
The RV industry uses non-standard sizes to maximize floor space in campers, trailers, and motorhomes. That's smart engineering. The problem is that RV manufacturers typically install the cheapest mattresses possible to keep costs down. They know you're buying the RV for the RV, not the mattress.
So you end up sleeping on a thin piece of foam that was never meant to last.
Complete RV Mattress Size Chart
| RV Mattress Size | Dimensions | Closest Standard | Difference | Common In |
|---|---|---|---|---|
| RV Short Queen | 60" × 75" | Queen (60×80) | 5" shorter | Most travel trailers, fifth wheels |
| RV King | 72" × 80" | Cal King (72×84) | 4" shorter | Large motorhomes, luxury RVs |
| RV Queen | 60" × 74" | Queen (60×80) | 6" shorter | Some older RVs |
| RV Three-Quarter | 48" × 75" | Full (54×75) | 6" narrower | Camper vans, vintage trailers |
| RV Full | 53" × 75" | Full (54×75) | 1" narrower | Smaller RVs |
| RV Twin | 34" × 75" | Twin (38×75) | 4" narrower | Bunk areas |
| Narrow RV Bunk | 30" × 75" | Twin (38×75) | 8" narrower | Over-cab bunks, kid bunks |
| Truck Camper | 28" × 75" | Cot | Custom | Truck bed campers |
Why Standard Mattresses Won't Work
Every RV size is slightly smaller than its standard counterpart. The 4-6 inch difference doesn't sound like much, but it means a standard mattress simply won't fit. You'll be stuck trying to force it in or leaving it hanging over the platform.
The good news: companies like Mattress Insider and Custom Mattress Factory specialize in RV sizes and can make quality mattresses in any dimension.
RV Short Queen (60×75)
Dimensions: 60" wide × 75" long (5" shorter than a standard Queen)
Who uses it: Most common RV mattress size. Found in travel trailers, fifth wheels, Class A/B/C motorhomes.
The problem: The Short Queen is close enough to a standard Queen (60×80) that people try to use regular Queen sheets and bedding. They don't fit right. And when they go to replace the mattress, they discover standard Queens are 5 inches too long for their RV bedroom.
What I See
Thin foam mattresses (4-6 inches) that have completely broken down. Body impressions. Sagging. Foam that crumbles when moved. Owners who've been sleeping on them for 10+ years because they didn't know quality RV Short Queens existed.
What to Look For:
- Minimum 8-10" thickness (more support than cheap 4-6" RV mattresses)
- Density rating of 1.8+ lb/ft³ for foam (cheap RV mattresses are often 1.2-1.5)
- Innerspring or hybrid options exist — not just foam
- CertiPUR-US certified foam
RV Short Queen Buying Guide
60" × 75"
Detailed guide with specific product recommendations for RV Short Queen mattresses.
Read the Full Guide →RV King (72×80)
Dimensions: 72" wide × 80" long (4" narrower than a standard King, same width as California King but shorter length)
Who uses it: Larger motorhomes, luxury fifth wheels, some travel trailers with slide-outs.
The problem: People confuse RV King with standard King (76×80) or California King (72×84). None of them are interchangeable. Order the wrong size and it either won't fit or you'll have gaps.
| Size | Width | Length | Interchangeable? |
|---|---|---|---|
| RV King | 72" | 80" | No |
| Standard King | 76" | 80" | Too wide for RV |
| California King | 72" | 84" | Too long for RV |
RV King Buying Guide
72" × 80"
Detailed recommendations for quality RV King mattresses.
Read the Full Guide →RV Bunk Mattresses (Various Sizes)
Common dimensions:
- 30" × 75" (Narrow Twin / Cot)
- 28" × 75"
- 30" × 80"
- 34" × 75"
- Custom sizes depending on RV model
Who uses it: RV bunk beds, typically for kids or occasional guests.
The problem: Even more variation than regular RV mattresses. Every manufacturer seems to use slightly different bunk dimensions. You often need to measure your exact space and order custom.
What to Look For:
- Measure your exact bunk dimensions (don't assume)
- 4-6" thickness is usually appropriate for bunks (clearance issues)
- Foam is fine for occasional use; spring options for frequent use
- Consider weight limits if adults will use them
RV Bunk Mattress Buying Guide
Various Sizes
Detailed recommendations for RV bunk mattresses in all common sizes.
Read the Full Guide →RV Three-Quarter (48×75)
Dimensions: 48" wide × 75" long
Who uses it: Smaller RVs, camper vans, vintage trailers.
Note: Same as the standard Three-Quarter size (see below), but often found in RV applications.
Three-Quarter Mattress Guide
48" × 75"
I've written a complete guide to Three-Quarter mattresses with specific product recommendations.
Read the Full Guide →Truck & Vehicle Mattresses
Complete Truck & Vehicle Mattress Size Chart
| Vehicle Type | Common Sizes | Notes |
|---|---|---|
| Semi-Truck (Standard) | 42" × 80" | Most common sleeper cab size |
| Semi-Truck (Narrow) | 38" × 80" | Older cabs, some day cabs |
| Semi-Truck (Compact) | 35" × 79" | European-style cabs |
| Freightliner Cascadia | 42" × 80" | Standard sleeper |
| Peterbilt 579 | 42" × 80" | Standard sleeper |
| Kenworth T680 | 42" × 80" | Standard sleeper |
| Volvo VNL | 42" × 80" | Some models vary |
| Boat V-Berth | Custom tapered | Requires template |
| Boat Cabin | Varies widely | Often 54" × 74" or smaller |
Semi-Truck Sleeper Mattresses
Common dimensions:
- 42" × 80" (most common)
- 38" × 80"
- 35" × 79"
- Custom sizes depending on cab manufacturer
Who uses it: Long-haul truckers who sleep in their cab 200+ nights per year.
The problem: Truckers sleep on their mattress MORE than most people sleep on their home mattress. But the options marketed to them are often the worst quality available — thin foam pads designed to hit a $99 price point.
What I See
Truckers are hard on mattresses. The constant vibration of the road, temperature fluctuations in the cab, and heavy nightly use means these mattresses wear out fast. I've removed truck mattresses that were completely destroyed after just 2-3 years.
What to Look For:
- Higher density foam than standard (1.8+ lb/ft³ minimum)
- 6-8" thickness minimum for nightly use
- Consider cooling features (truck cabs get hot)
- Waterproof cover or protector (condensation is common)
- Some truckers prefer innerspring for airflow
Why Quality Matters More Here
If you sleep in your truck 250 nights a year, a cheap mattress isn't saving you money — it's costing you sleep. The difference between a $150 foam pad and a $400 quality mattress is $1 per night over a year. Worth it.
Boat & Marine Mattresses
Dimensions: Highly variable — V-berth, custom shapes, tapered corners
Who uses it: Sailboats, yachts, houseboats, cabin cruisers.
The problem: Boat mattresses often need custom shapes (tapered, V-shaped, curved corners). Standard rectangular mattresses don't fit. And marine environments add challenges: moisture, salt air, limited ventilation, mold risk.
What I See
Boat mattresses are some of the worst-condition odd-size mattresses I remove. The marine environment accelerates breakdown. Mold is common. Foam disintegrates. Many boat owners don't even realize how bad their mattress has gotten because they only use it occasionally.
What to Look For:
- Moisture-resistant or marine-grade foam
- Antimicrobial treatment
- Custom shape capability (many marine mattress companies offer this)
- Ventilated base or moisture barrier
- Mold-resistant materials
Custom shapes: Most boat mattresses require custom templates. Companies like Mattress Insider specialize in marine mattresses and will work with you to create a template, or may have templates for common boat models on file.
Oversized Mattresses
For families who need more room than a standard King, oversized mattresses have become increasingly popular. But they come with challenges: finding sheets, fitting through doorways, and knowing where to buy quality options.
Complete Oversized Mattress Size Chart
| Size | Dimensions | Square Feet | vs. King | Best For | Sheets Available? |
|---|---|---|---|---|---|
| Standard King | 76" × 80" | 42.2 sq ft | Baseline | Couples | Everywhere |
| California King | 72" × 84" | 42.0 sq ft | Same area | Tall sleepers | Everywhere |
| Wyoming King | 84" × 84" | 49.0 sq ft | +16% | Couples + pet or child | Specialty retailers |
| Texas King | 80" × 98" | 54.4 sq ft | +29% | Tall people, families | Specialty retailers |
| Alberta King | 96" × 96" | 64.0 sq ft | +52% | Co-sleeping families | Very limited |
| Alaskan King | 108" × 108" | 81.0 sq ft | +92% | Large families | Custom only |
| Family Bed (2 Kings) | 152" × 80" | 84.4 sq ft | +100% | Co-sleeping families | King sheets × 2 |
Room Size Requirements
An Alaskan King (108" × 108") is 9 feet by 9 feet. You'll need at least a 14' × 14' bedroom to fit it with walking room. Most master bedrooms are 12' × 12' — too small for anything larger than a Texas King.
For oversized mattresses, Big Mattress Co and Alaskan King Beds are among the few companies that specialize in these massive sizes with quality construction.
Texas King (80×98)
Dimensions: 80" wide × 98" long (wider and longer than a standard King)
Who uses it: Tall people (6'4"+), co-sleeping families, couples who want maximum space, people with large bedroom suites.
The problem: Only a handful of manufacturers make Texas King mattresses. Even fewer make quality ones. The same is true for bed frames, sheets, and bedding. It's a niche market with limited options.
What I See
Oversized mattresses are often custom orders that people keep forever — both because they're expensive and because finding a replacement feels impossible. I've removed oversized mattresses that should have been replaced a decade ago.
What to Look For:
- Same quality indicators as standard mattresses (foam density, spring quality)
- Verify the manufacturer makes the mattress in-house vs. cutting down a larger piece
- Check sheet availability BEFORE buying the mattress
- Measure your bedroom and doorways — these are heavy and hard to maneuver
Wyoming King (84×84)
Dimensions: 84" wide × 84" long (square shape)
Who uses it: Similar to Texas King — families, tall people, those who want extra width without extra length.
The difference from Texas King: Wyoming King is square (84×84). Texas King is rectangular (80×98). Choose based on whether you need more width or more length.
Alaskan King (108×108)
Dimensions: 108" wide × 108" long (9 feet × 9 feet)
Who uses it: Large co-sleeping families (parents + multiple children), people with very large bedrooms, those who want maximum sleeping space.
The problem: At 9×9 feet, this is essentially a small room. Finding a frame, sheets, and bedding is a challenge. Moving it is nearly impossible without disassembly. Very few manufacturers make them.
Logistical Considerations
- Will it fit through your doors and hallways? (Probably not in one piece)
- Where will you buy sheets? (Very limited options)
- What frame will you use? (Usually custom or specialized)
- Can you physically move it? (You'll need help)
Family Bed / Co-Sleeping
Common configurations:
- Two Kings pushed together (152" × 80")
- King + Twin side by side
- Wyoming King (84×84)
- Alaskan King (108×108)
- Custom configurations
Who uses it: Families who practice co-sleeping with multiple children.
What to Look For:
- Gap fillers / bed bridges if using two mattresses
- Fitted sheets designed for the specific configuration
- Edge support (kids roll)
- Consider waterproof protection
Split Mattresses
Split mattresses are designed for adjustable bed bases, allowing each side to move independently. They're not technically "odd sizes" in dimensions, but they're specialized enough that many people struggle to find good options.
Complete Split Mattress Size Chart
| Split Size | Each Piece | Total Size | Availability | Notes |
|---|---|---|---|---|
| Split King | 38" × 80" (×2) | 76" × 80" | Common | Uses standard Twin XL |
| Split Queen | 30" × 80" (×2) | 60" × 80" | Limited | Non-standard piece size |
| Split California King | 36" × 84" (×2) | 72" × 84" | Very limited | Non-standard piece size |
| Split Full | 27" × 75" (×2) | 54" × 75" | Rare | For smaller adjustable bases |
Why Split King is Easiest
Split King uses two standard Twin XL mattresses — a size that's widely available. Any other split size requires specialty pieces that are harder to find and more expensive.
Split King
Dimensions: Two 38" × 80" pieces (Twin XL × 2) = 76" × 80" total
Who uses it: Couples with adjustable bed bases who want independent movement (one person can raise their head while the other sleeps flat).
The problem: Any Twin XL mattress technically works, but mismatched mattresses create a ridge in the middle. Many people want to buy a matched set designed to work together.
What to Look For:
- Matched pair designed for split king use
- Similar feel/firmness even if preferences differ slightly
- Consider a mattress bridge/gap filler for the center
- Check adjustable base compatibility
Split Queen
Dimensions: Two 30" × 80" pieces = 60" × 80" total
Who uses it: Couples who want adjustable base flexibility but have a Queen-size bedroom.
The problem: Split Queen is much less common than Split King. Fewer manufacturers make them. 30×80 is a non-standard size that you can't just find anywhere.
Split California King
Dimensions: Two 36" × 84" pieces = 72" × 84" total
Who uses it: Tall couples with adjustable bases who need the extra length of a California King.
The problem: Even more specialized than Split Queen. Very limited options.
Other Non-Standard Sizes
Complete Non-Standard Size Chart
| Size Name | Dimensions | Closest Standard | Difference | Common Uses |
|---|---|---|---|---|
| Olympic Queen | 66" × 80" | Queen (60×80) | 6" wider | Hotels, couples needing more room |
| Three-Quarter (3/4) | 48" × 75" | Full (54×75) | 6" narrower | Antique beds, RVs, small rooms |
| Full XL | 54" × 80" | Full (54×75) | 5" longer | Tall single sleepers, dorms |
| Narrow Twin / Cot | 30" × 75" | Twin (38×75) | 8" narrower | Cots, bunks, daybeds |
| Super Single | 48" × 84" | Twin XL (38×80) | 10" wider, 4" longer | Tall single sleepers |
| Antique Full | 48" × 72" | Full (54×75) | 6" narrower, 3" shorter | Pre-1950s bed frames |
| Antique 3/4 | 48" × 72" | Three-Quarter | 3" shorter | Vintage furniture |
| European Single | 36" × 75" | Twin (38×75) | 2" narrower | European bed frames |
| European Double | 55" × 79" | Full (54×75) | 1" wider, 4" longer | European bed frames |
The Three Sizes I See Most Often
Olympic Queen, Three-Quarter, and Full XL account for about 80% of the non-standard sizes I remove. If you have one of these, I've written detailed guides with specific recommendations (highlighted above).
Olympic Queen (66×80)
Dimensions: 66" wide × 80" long (6" wider than a standard Queen)
Who uses it: Couples who want more width than a Queen but don't have room for a King. Common in older hotels, some RVs, and smaller master bedrooms.
The problem: Olympic Queen was more popular in the 1980s-90s. Today, fewer manufacturers make them, and finding sheets is challenging.
Olympic Queen Mattress Guide
66" × 80"
I've written a complete guide to Olympic Queen mattresses with specific product recommendations.
Read the Full Guide →Three-Quarter / 3/4 Size (48×75)
Dimensions: 48" wide × 75" long (between a Twin and a Full)
Who uses it: Antique bed frames, small bedrooms, guest rooms, RVs, dorm rooms.
The problem: Three-Quarter was a standard size decades ago but has largely been replaced by Twin XL and Full. Finding modern mattresses in this size requires knowing where to look.
Three-Quarter Mattress Guide
48" × 75"
I've written a complete guide to Three-Quarter mattresses with specific product recommendations.
Read the Full Guide →Narrow Twin / Cot Size (30×75)
Dimensions: 30" wide × 75" long (8" narrower than a standard Twin)
Who uses it: Cots, RV bunks, small guest spaces, daybeds, military barracks.
What to Look For:
- Consider the use case — occasional guest use vs. nightly use
- Thickness may be limited by frame or space constraints
- Quality foam still matters even at smaller sizes
Narrow Twin / Cot Mattress Guide
30" × 75"
I've written a complete guide to narrow twin and cot size mattresses with specific product recommendations.
Read the Full Guide →Super Single (48×84)
Dimensions: 48" wide × 84" long (also called "Extended Three-Quarter")
Who uses it: Tall single sleepers, some waterbeds, specialty frames.
Full XL (54×80)
Dimensions: 54" wide × 80" long (5" longer than a standard Full)
Who uses it: Tall single sleepers, college dorms (some), guest rooms.
The problem: Full XL is uncommon enough that many people don't even know it exists. It's a great option for tall individuals who don't need the width of a Queen but want more length than a standard Full.
Full XL Mattress Guide
54" × 80"
I've written a complete guide to Full XL mattresses with specific product recommendations.
Read the Full Guide →Split California King (36×84 per half)
Dimensions: Two mattresses, each 36" wide × 84" long (72" × 84" combined)
Who uses it: Couples with adjustable bases who want independent movement, couples with different firmness preferences, taller individuals who need the extra 4" length.
The problem: Split King (Twin XL) is everywhere. Split California King? Most retailers don't stock it. The 36" × 84" dimensions don't match any standard mattress size, making it hard to find.
Split California King Mattress Guide
36" × 84" each (72" × 84" total)
I've written a complete guide to Split Cal King mattresses with specific product recommendations.
Read the Full Guide →Antique Bed Sizes
Common antique dimensions:
- 48" × 72" (common antique "full")
- 54" × 72"
- 52" × 74"
- 3/4 size variations
- Completely custom sizes
Who uses it: Anyone with an antique bed frame — inherited furniture, vintage collectors, historic home restorations.
The problem: Antique beds predate mattress standardization. A bed from 1920 might be 54×72, 52×75, or some other dimension that doesn't match anything sold today.
What to Do
- Measure your antique frame EXACTLY (inside dimensions)
- Check if any standard or known odd-size is close enough
- If not, order a true custom-size mattress
- Consider a mattress topper to fine-tune fit
Custom is often the only option: Many antique beds require true custom mattresses. Companies like Custom Mattress Factory and Mattress Insider specialize in making mattresses to your exact dimensions — just send them your measurements.
Specialty Mattresses
Complete Specialty Mattress Size Chart
| Specialty Type | Common Sizes | Max Thickness | Key Requirement |
|---|---|---|---|
| Bunk Bed (Upper) | Twin (38×75), Twin XL (38×80) | 6-8" | Below guard rail height |
| Bunk Bed (Lower) | Twin, Full (54×75) | 8-10" | Head clearance to upper bunk |
| Trundle Bed | Twin (38×75), Narrow (30×75) | 5-8" | Must slide under main bed |
| Daybed | Twin (38×75), Twin XL (38×80) | 8-10" | Firm enough for sitting |
| Sofa Bed | Full (54×75), Queen (60×80) | 4-6" | Must fold into sofa frame |
| Murphy Bed | Twin, Full, Queen | 10-12" | Cabinet depth clearance |
| Rollaway / Folding | Twin (38×75), Narrow (30×75) | 4-5" | Must fold with frame |
Thickness is Critical
Unlike regular mattresses where thicker is usually better, specialty mattresses have strict thickness limits. A sofa bed mattress that's too thick won't fold. A bunk mattress that's too thick becomes a safety hazard. Always measure your clearances first.
Bunk Bed Mattresses
Common dimensions:
- Twin (38×75) — most common
- Twin XL (38×80)
- Full (54×75)
- Custom/narrow sizes for space-saving bunks
Key Considerations:
- Thickness: Must fit within bunk frame with adequate rail height (6-8" typically)
- Weight: Upper bunk mattresses shouldn't be excessively heavy
- Safety: Top of mattress should be well below guard rail
- Edge support: Kids roll — good edge support matters
Trundle Bed Mattresses
Common dimensions:
- Twin (38×75) but thinner profile
- Narrow Twin (30×75)
- Full (54×75) thin profile
Key consideration: Trundle mattresses must be thin enough to slide under the main bed — typically 5-8" maximum thickness depending on trundle frame.
The Trade-off
Thinner mattresses mean less support. For occasional guest use, this is fine. For nightly use, consider whether a trundle is the right furniture choice.
Daybed Mattresses
Common dimensions:
- Twin (38×75) — most common
- Twin XL (38×80)
Key consideration: Daybeds function as both seating and sleeping. You need a mattress that's comfortable for sitting during the day AND sleeping at night. Many people prefer firmer options that don't sag when used as a couch.
Sofa Bed Mattresses
Common dimensions:
- Full (54×75) — most common
- Queen (60×80)
- Twin (38×75)
The problem: Stock sofa bed mattresses are notoriously terrible — thin, uncomfortable, and made to a price point. Replacing them with a quality mattress dramatically improves the sleeping experience.
What to Look For:
- Measure your specific sofa bed frame (they vary)
- 4-6" thickness maximum (must fold into sofa)
- Memory foam works well (folds easily, doesn't spring back)
- Consider how often it's used — occasional guests vs. regular use
How to Measure for an Odd-Size Mattress
Getting the right size is critical. Here's how to measure correctly:
Step 1: Remove the Old Mattress
Don't measure with the old mattress in place — it may have compressed or shifted.
Step 2: Measure the Inside of the Frame
Measure the interior dimensions where the mattress sits:
- Width: Side to side, inside edge to inside edge
- Length: Head to foot, inside edge to inside edge
- Depth: How much mattress thickness your frame can accommodate (for bunks, trundles, etc.)
Step 3: Measure in Multiple Spots
Old frames can warp. Measure width at the head, middle, and foot. Measure length on both sides. Use the smallest measurement to ensure fit.
Step 4: Account for Clearance
You want a mattress that fits snugly but not so tight you can't change sheets. Allow 1/2" to 1" of total clearance.
Step 5: Document Everything
Write down your measurements. Take photos of the frame. When ordering custom, you'll need this information.
Common Measurement Mistakes
- Measuring the old mattress (it's compressed)
- Measuring outside of frame instead of inside
- Assuming standard sizes without measuring
- Forgetting to measure depth/height restrictions
What to Look For in an Odd-Size Mattress
Just because a mattress is an odd size doesn't mean you should accept lower quality. Here's what matters:
Foam Density
What it is: How much material is packed into the foam, measured in pounds per cubic foot (lb/ft³).
Why it matters: Low-density foam breaks down faster. This is the #1 reason cheap RV and truck mattresses fall apart in 1-2 years.
| Density | Quality Level | Expected Lifespan |
|---|---|---|
| 1.0-1.5 lb/ft³ | Low (cheap RV mattresses) | 1-3 years |
| 1.5-1.8 lb/ft³ | Medium | 3-5 years |
| 1.8-2.5 lb/ft³ | Good | 5-8 years |
| 2.5+ lb/ft³ | High | 8+ years |
What I See
Most of the destroyed odd-size mattresses I remove are low-density foam that was never meant to last. The foam crumbles, the body impressions are permanent, and sometimes you can poke a finger right through it.
Thickness
General rule: Thicker mattresses typically offer better support and durability. But thickness must fit your application. For a deep dive into what different thickness ranges are actually for and how construction matters more than height, see my complete mattress thickness guide.
| Use Case | Recommended Thickness |
|---|---|
| Primary bed (nightly use) | 8-12" |
| RV/Truck (nightly use) | 8-10" |
| RV/Truck (occasional) | 6-8" |
| Bunk bed | 6-8" |
| Trundle | 5-6" (frame dependent) |
| Sofa bed | 4-6" (must fold) |
Construction Type
- All foam: Easiest to ship/transport, good for adjustable bases, can sleep hot
- Innerspring: Traditional support, better airflow, heavier
- Hybrid: Combines foam top with spring support, best of both worlds, heaviest
If you're considering an innerspring or hybrid, coil quality matters. Here's what I see when I tear mattresses open:
Certifications
- CertiPUR-US: Foam is made without harmful chemicals
- OEKO-TEX: Tested for harmful substances
- GREENGUARD: Low emissions
Edge Support
How well the mattress holds up when you sit or sleep near the edge. Important for smaller odd sizes where you might be closer to the edge than on a King.
Where to Buy Custom & Odd-Size Mattresses
I've tested dozens of odd-size mattresses and written detailed buying guides with my top recommendations. If you're looking for a specific size, start here:
My Odd-Size Mattress Buying Guides
Olympic Queen Mattress Guide
66" × 80"
My top picks, what to avoid, where to find sheets, and which brands actually make quality Olympic Queens.
Where to Buy →Three-Quarter Mattress Guide
48" × 75"
Best options for antique beds, RVs, and small spaces. Includes budget picks and premium recommendations.
Where to Buy →Full XL Mattress Guide
54" × 80"
The best Full XL mattresses for tall sleepers. Where to buy and which brands to trust.
Where to Buy →Split Cal King Guide
36" × 84" each
The best Split California King mattresses for adjustable bases. Where to buy this hard-to-find size.
Where to Buy →More Guides Coming Soon
I've completed detailed buying guides for RV mattresses including RV Short Queen, RV King, and RV Bunk. Alaskan King and other popular odd sizes coming soon. Learn more about my testing process.
What to Ask Before Buying
- What foam density do you use?
- Is this made to order or cut from a larger piece?
- What's the return policy for custom sizes?
- What's the warranty?
- How long until delivery?
Custom & Odd-Size Mattress Manufacturers
These companies specialize in non-standard sizes and custom orders:
| Company | Specializes In | Custom Sizes? |
|---|---|---|
| Mattress Insider | RV, Boat, Truck, Antique, Custom shapes | Yes — any size |
| Custom Mattress Factory | RV, Antique beds, Odd dimensions | Yes — any size |
| Big Mattress Co | Oversized (Texas, Wyoming, Alaskan King) | Yes |
| Alaskan King Beds | Oversized kings, Family beds | Yes |
| Brooklyn Bedding | RV sizes, Split sizes, Some custom | Limited options |
Red Flags to Avoid
- No density specifications listed
- Prices significantly below competitors (usually means low-quality materials)
- No reviews or only reviews on their own site
- No warranty or very short warranty (less than 5 years)
- Won't answer questions about materials
Frequently Asked Questions
Why I Created This Guide
I've been in the mattress recycling business since 2011. I've processed over 1.15 million mattresses across all 50 states.
And I've seen what happens when people can't find replacement mattresses.
They sleep on worn-out beds for years. They develop back problems. They buy the cheapest thing available and replace it again in two years. They don't realize quality options exist.
This guide exists because no one should have to sleep on a 15-year-old mattress just because it's a non-standard size. Quality odd-size mattresses are out there — you just need to know where to look.
My Odd-Size Mattress Guides
I've written detailed buying guides for the most common odd sizes, with specific product recommendations:
Olympic Queen Mattress Guide
66" × 80"
Complete guide with top picks and what to avoid.
Read Guide →Three-Quarter Mattress Guide
48" × 75"
Complete guide with top picks and what to avoid.
Read Guide →RV Mattress Guide
All RV Sizes
Complete hub for all RV mattress sizes and buying advice.
Read Guide →