Twin XL Mattress Size Guide
The Twin XL is 5 inches longer than a standard Twin — the most popular dorm size and ideal for taller solo sleepers. Pairs into a Split King when used with an adjustable base.
About the Twin XL Size
The Twin XL adds 5 inches of length to the standard Twin footprint, making it 38 inches wide by 80 inches long. It's the standard college dormitory size across the US, replacing standard Twin frames in most university housing. The extra length accommodates taller adults (up to 6'4") without requiring a Full or Queen, making it ideal for small bedrooms where width is a constraint but height is a concern. Twin XL is also the building block of a Split King: two Twin XL mattresses side by side equal the dimensions of a King (76 inches wide), allowing adjustable base users and couples with different firmness needs to each sleep on their preferred mattress while sharing a King-size bed frame. This makes the Twin XL a surprisingly practical choice well beyond dormitories.
Best For
- ✓College dormitories
- ✓Tall adults (up to 6'4")
- ✓Adults in small rooms needing length
- ✓Split King configurations (pairs to King)
- ✓Adjustable base users
Not Ideal For
- ✗Couples sharing one mattress
- ✗Children (standard Twin is sufficient and cheaper)
- ✗Wide sleepers
Top Mattresses Available in Twin XL
Best for: Budget shoppers · Guest rooms
Why it stands out: Individually encased springs add support and airflow
Keep in mind: The 8-inch profile provides less cushioning than taller hybrids
Best for: Budget shoppers · Back sleepers
Why it stands out: Cooling gel Memory Foam and a cool-to-touch top fabric
Keep in mind: Firm feel provides less cushioning than the taller Relax and Supreme
Best for: Budget shoppers · Back sleepers
Why it stands out: Low current pricing for a foam-and-coil hybrid
Keep in mind: This legacy route represents the same current Walmart item as the 10-inch Hybrid catalog row
Best for: Budget shoppers · Side sleepers
Why it stands out: Three-inch memory-foam comfort layer gives the Medium more contouring than a thin budget foam bed
Keep in mind: Deep memory-foam contouring can feel slower to move on than a hybrid
Buy with confidence
Try Lucid's current 10-inch Medium at home for 100 nights at Lucid
Best for: Side sleepers · Back sleepers
Why it stands out: Cool-to-touch top panel and three-zone foam
Keep in mind: Exact foam densities and cover fiber content are not published
Best for: Value focused shoppers who want a conventional medium firm memory foam feel · Back and stomach sleepers who do not need an extra firm surface
Why it stands out: Certification scope is specific: CertiPUR-US covers the foam layers and OEKO-TEX STANDARD 100 covers only the knit cover; Bare Home separately states that the mattress is fiberglass-free
Keep in mind: Only one feel is offered, and Bare Home itself says lighter side sleepers may prefer something softer
Buy with confidence
100-night Good Dreams comfort trial at Bare Home
Twin XL Size — Frequently Asked Questions
Is Twin XL the same as a dorm bed?
Yes — US college dormitories standardized on Twin XL (38×80 inches) decades ago. When shopping for dorm bedding, always confirm it's Twin XL, not standard Twin (which is 5 inches shorter).
How does Twin XL become a Split King?
Two Twin XL mattresses placed side by side equal the width and length of a King (76×80 inches). This is the foundation of the Split King configuration, popular with couples who want independent adjustable bases or different mattress firmness on each side.
Is Twin XL worth it over Twin?
If you're under 5'9" and the standard Twin length is sufficient, Twin XL adds cost without benefit. If you're taller or the bed will double as a college dorm choice, Twin XL is the right pick.
Are Twin XL sheets hard to find?
Not in the US — Twin XL sheets are widely available at most major retailers, both in-store and online. They're less common internationally, so verify sizing if ordering abroad.
Can a Twin frame fit a Twin XL mattress?
No. A Twin frame is 75 inches long; a Twin XL is 80 inches. The mattress would hang off the end of a standard Twin frame. Always purchase a Twin XL-specific frame for a Twin XL mattress.