Medium Extra Firm King Size Mattresses
76” wide by 80” long
Extra firm mattresses are the firmest, most supportive feel we carry — a hard, no-sink surface that holds your body on top of the mattress rather than letting it settle in. They're built for stomach sleepers, heavier-weight sleepers and anyone who finds a standard firm mattress still too soft, delivering maximum support and spinal alignment. Most use a tight-top or high-density foam construction (including orthopedic Chirofoam), with budget-friendly options that keep extra-firm support affordable. Shop Beautyrest, Serta, Chirofoam, Springwall and our own NM line — from $152, with free delivery across Canada. • Feel: extra firm is the firmest of our four comfort levels — a hard, no-sink surface • Best for: stomach sleepers, heavier-weight sleepers, and anyone who wants maximum support • Choose this over firm if a standard firm mattress still feels too soft • Consider firm or medium if you sleep on your side or want any cushioning • Constructions: tight-top and high-density foam (including orthopedic Chirofoam) • Brands: Beautyrest, Serta, Chirofoam, Springwall & NM • Prices: from $152 — an affordable, value-focused selection
A king mattress measures 76” wide by 80” long — the widest standard mattress size, giving each partner 38 inches of personal space (the same width as a twin).
It’s the top choice for couples who want maximum sleeping room, families who co-sleep with young children, anyone with a larger master bedroom, and sleepers who simply prefer to spread out.
Every king mattress at National Mattress ships free across Canada with a 365-night sleep trial, price match guarantee, and 5–25 year manufacturer’s warranty.
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How to Choose a King Size Mattress in Canada
A standard Canadian king mattress measures 76″ × 80″ (193 cm × 203 cm), providing each partner with 38 inches of personal sleeping width, roughly the same as a Twin XL. That extra space makes a king ideal for couples, co-sleeping families, and anyone who simply prefers room to stretch. Ensure your bedroom has at least 12″ × 12″ (3.7 m × 3.7 m) of floor space so you can walk comfortably around the bed. If a standard king is too wide, consider a Queen (60″ × 80″) instead.
National Mattress carries a wide range of king mattresses across five construction types: eurotop/pillowtop, traditional tight-top, memory foam, hybrid, and latex. Pocket-coil and hybrid models with zoned lumbar support suit back sleepers who need spinal alignment, while memory foam and plush eurotops conform to pressure points for side sleepers. Over 91% of our king mattresses are compatible with adjustable bases, and every model carries CertiPUR-US® certification for foam safety.
Many Models, 10 Brands
Shop king mattresses from Serta, Beautyrest, Sealy, Tempur-Pedic, Springwall, Stearns & Foster, iComfort, Chirofoam, Evergreen, and NM.
A Range of Budgets
From budget-friendly great-value foam models to luxury Tempur-Pedic and Stearns & Foster collections, king mattresses across a range of budgets.
Canadian-Made
100% of National Mattress mattresses are manufactured in Canadian factories with CertiPUR-US® certified foams and free delivery coast to coast.
91% Adjustable-Base Ready
Most king mattresses work with adjustable bases, check individual product pages for compatibility or browse our top picks.
Frequently Asked Questions About King Size Mattresses
What are the dimensions of a king size mattress in Canada?
How much should I spend on a king size mattress?
What type of king mattress is best for couples?
Can I use a king mattress on an adjustable base?
Do king size mattresses ship free across Canada?
What firmness level should I choose for a king mattress?
Not Sure Which King Mattress Is Right for You?
Our non-commissioned sleep experts match you to the perfect king mattress based on your sleep style, body type, and budget, no sales pressure, just honest guidance.
Upgrade your sleep at National Mattress
Discover a mattress that transforms your sleep into a truly rejuvenating experience. We offer a wide variety of options to suit every sleep style and preference, ensuring a better night's sleep.
Why Choose Us?
- Variety: From plush to firm, we have options for every body type and sleep style.
- Quality: Trusted brands and top-notch materials for long-lasting comfort.
- Sleep Trials & Warranties: Enjoy peace of mind with flexible trials and warranties.
- Expert Advice: Get personalized recommendations from our sleep specialists.
Mattress Selection Includes
- Memory Foam: Contours to your body for personalized comfort and pressure relief.
- Hybrid: Combines responsive springs with foam for balanced support and comfort.
- Innerspring: Provides firm support, bounce, and cooling airflow.
- Latex: Hypoallergenic, eco-friendly, and exceptionally comfortable.
- Adjustable Beds: Customize your sleep position for optimal comfort.
