Firm Height 84 Mattresses

Explore Firm Height 84 Mattresses at Mattress Firm to find a selection of mattresses in a firm feel and 84-inch size. Compare available options by comfort preference, size and budget to find the right fit for your bedroom and sleep routine.

Beautyrest Black Series Two 14.25" Firm Mattress

365

Starting at

$3499⁰⁰

$3899⁰⁰

$400 OFF

Firm Comfort, best for

Back, Stomach Sleepers
Pain
Bed Partner
Temperature
Toss and Turn

$300 ⁶ adjustable base instant gift with purchase.

Serta Perfect Sleeper Pacific Peace 12" Hybrid Firm Mattress

244

Starting at

$1399⁰⁰

Firm Comfort, best for

Back, Stomach Sleepers
Pain
Bed Partner
Temperature
Toss and Turn

FREE ADJUSTABLE BASE ³ with code ELEVATE

Serta Classic Blissville 12.5" Firm Mattress

313

Starting at

$1799⁹⁹

Firm Comfort, best for

Back, Stomach Sleepers
Pain
Temperature
Bed Partner
Toss and Turn

FREE ADJUSTABLE BASE ³ with code ELEVATE

Beautyrest Black Series Three 15" Firm Mattress

2312

Starting at

$4199⁰⁰

$4799⁰⁰

$600 OFF

Firm Comfort, best for

Back, Stomach Sleepers
Pain
Bed Partner
Temperature
Toss and Turn

$300 ⁶ adjustable base instant gift with purchase.

Serta Perfect Sleeper Sleep Excellence Firm Mattress

279

Starting at

$1699⁹⁹

Firm Comfort, best for

Back, Stomach Sleepers
Pain
Toss and Turn
Temperature
Bed Partner

FREE ADJUSTABLE BASE ³ with code ELEVATE

Beautyrest BR800 Greenwood 11.25" Firm Mattress

1723

Starting at

$619⁹⁹

$1299⁹⁹

$680 OFF

Firm Comfort, best for

Back, Stomach Sleepers
Bed Partner
Toss and Turn
Temperature
Pain

FREE ADJUSTABLE BASE ³ with code ELEVATE

Beautyrest BR800 11.25" Firm Mattress

2260

Starting at

$1299⁹⁹

Firm Comfort, best for

Back, Stomach Sleepers
Toss and Turn
Pain
Bed Partner
Temperature

FREE ADJUSTABLE BASE ³ with code ELEVATE

Beautyrest Black Hybrid Series Three 14.5" Firm Mattress

108

Starting at

$4099⁰⁰

$4699⁰⁰

$600 OFF

Firm Comfort,

Pain
Bed Partner
Temperature
Toss and Turn

$300 ⁶ adjustable base instant gift with purchase.

Serta Perfect Sleeper Nurture Night 12" Firm Mattress

1235

Starting at

$999⁰⁰

Firm Comfort, best for

Back, Stomach Sleepers
Pain
Bed Partner
Temperature
Toss and Turn

FREE ADJUSTABLE BASE ³ with code ELEVATE

Sleepy's Rest Firm 2.0 Innerspring Mattress

7039

Starting at

$449⁹⁹

Firm Comfort, best for

Back, Stomach Sleepers
Pain
Bed Partner
Temperature
Toss and Turn

Beautyrest Black Series Three 14.25" Extra Firm Mattress

298

Starting at

$4199⁰⁰

$4799⁰⁰

$600 OFF

Firm Comfort, best for

Back, Stomach Sleepers
Pain
Bed Partner
Temperature
Toss and Turn

$300 ⁶ adjustable base instant gift with purchase.

Kingsdown Crown Imperial 15" Firm Mattress

Starting at

$4599⁰⁰

$5999⁰⁰

$1400 OFF

Firm Comfort, best for

Back, Stomach Sleepers
Pain
Bed Partner
Temperature
Toss and Turn

FREE ADJUSTABLE BASE ³ with code ELEVATE

Sleepy's By Sealy Spring Firm Mattress

1402

Starting at

$1999⁹⁹

Firm Comfort, best for

Back, Stomach Sleepers
Pain
Bed Partner
Toss and Turn
Temperature

FREE ADJUSTABLE BASE ³ with code ELEVATE

Serta Perfect Sleeper Oasis Sleep 14.5" Firm Pillow Top Mattress

1232

Starting at

$1399⁰⁰

Firm Comfort, best for

Back, Stomach Sleepers
Pain
Bed Partner
Temperature
Toss and Turn

FREE ADJUSTABLE BASE ³ with code ELEVATE

Beautyrest Black Series Three 16.5" Firm Pillow Top Mattress

306

Starting at

$4599⁰⁰

$5199⁰⁰

$600 OFF

Firm Comfort, best for

Back, Stomach Sleepers
Pain
Bed Partner
Temperature
Toss and Turn

$300 ⁶ adjustable base instant gift with purchase.

Beautyrest Black Hybrid Series Four 16" Firm Apex Top Mattress

Starting at

$5899⁰⁰

$6599⁰⁰

$700 OFF

Firm Comfort,

Pain
Bed Partner
Temperature
Toss and Turn

$300 ⁶ adjustable base instant gift with purchase.

Beautyrest Black Series Four 17.5" Firm Summit Pillow Top Mattress

241

Starting at

$5899⁰⁰

$6599⁰⁰

$700 OFF

Firm Comfort, best for

Back, Stomach Sleepers
Pain
Bed Partner
Temperature
Toss and Turn

$300 ⁶ adjustable base instant gift with purchase.

Kingsdown Wesley 15.5" Firm Mattress

Starting at

$4199⁰⁰

$4799⁰⁰

$600 OFF

Firm Comfort, best for

Back, Stomach Sleepers
Pain
Bed Partner
Temperature
Toss and Turn

$300 ⁶ adjustable base instant gift with purchase.

Beautyrest Silver BRS900-C 14.5" Medium Mattress

814

Starting at

$1999⁹⁹

Medium Comfort, best for

Back, Side, Stomach Sleepers
Temperature
Pain
Bed Partner
Toss and Turn

FREE ADJUSTABLE BASE ³ with code ELEVATE

Beautyrest Black Series One 13.5" Extra Firm Mattress

722

Starting at

$2499⁰⁰

$2899⁰⁰

$400 OFF

Extra Firm Comfort, best for

Back, Stomach Sleepers
Pain
Allergies
Bed Partner
Toss and Turn
Temperature

$300 ⁶ adjustable base instant gift with purchase.

Beautyrest Black Series Three 16.25" Medium Pillow Top Mattress

487

Starting at

$4599⁰⁰

$5199⁰⁰

$600 OFF

Medium Comfort, best for

Back, Side, Stomach Sleepers
Pain
Bed Partner
Temperature
Toss and Turn

$300 ⁶ adjustable base instant gift with purchase.

Beautyrest Black Series Three 16.75" Plush Pillow Top Mattress

1520

Starting at

$4599⁰⁰

$5199⁰⁰

$600 OFF

Plush Comfort, best for

Side Sleepers
Bed Partner
Pain
Temperature
Toss and Turn

$300 ⁶ adjustable base instant gift with purchase.

Beautyrest BR800 11.5" Medium Firm Mattress

3260

Starting at

$1299⁹⁹

Medium Comfort, best for

Back, Side, Stomach Sleepers
Toss and Turn
Pain
Bed Partner
Temperature

Purple Rejuvenate Royale Crown Mattress

Starting at

$10399⁰⁰

$10899⁰⁰

$500 OFF

Plush Comfort, best for

Side Sleepers
Pain
Bed Partner
Temperature
Toss and Turn

$300 adjustable base instant gift with purchase.

Beautyrest Silver BRS900 11.75" Extra Firm Mattress

3337

Starting at

$1699⁹⁹

Extra Firm Comfort, best for

Back, Stomach Sleepers
Temperature
Pain
Allergies
Bed Partner
Toss and Turn

FREE ADJUSTABLE BASE ³ with code ELEVATE

Beautyrest BR800 Greenwood 11.5" Medium Firm Mattress

3243

Starting at

$589⁹⁹

$1299⁹⁹

$710 OFF

Medium Comfort, best for

Side, Back, Stomach Sleepers
Bed Partner
Toss and Turn
Temperature
Pain

Firm Height 84 mattresses are designed for sleepers who want a longer sleep surface and a firm, supportive feel. In most cases, an 84-inch mattress is associated with California King dimensions, measuring approximately 72 inches wide by 84 inches long, or with a Split California King made from two separate mattresses measuring about 36 inches wide by 84 inches long each. That extra length can make a meaningful difference for taller sleepers, especially when a standard mattress leaves feet close to or over the edge. It also gives couples more room to stretch out across a generous sleep surface. A firm mattress generally has less cushioning and sink than a medium or plush model, helping you feel more supported near the top of the bed rather than deeply cradled inside it. Many back and stomach sleepers prefer this steadier sensation because it can make it easier to maintain a comfortable, level position throughout the night. Combination sleepers may also appreciate a firm surface with enough responsiveness to make changing positions feel smooth. Firmness is personal, though, and body weight, sleep posture, shoulder and hip width and existing comfort preferences all influence how a mattress feels. A surface that feels comfortably firm to one sleeper may feel too rigid to another, so it helps to consider the complete design rather than relying on the firmness label alone.

The materials inside a firm 84-inch mattress affect its pressure relief, responsiveness, temperature feel and overall support. All-foam designs can provide an even, stable surface with motion isolation that may suit couples with different sleep schedules. Some include denser support foam beneath a more flexible comfort layer, creating a firm feel without making the entire mattress feel hard or unyielding. Innerspring and hybrid constructions typically combine coils with foam or other cushioning materials. Their responsive support can make moving across the surface easier, while the open space around the coils may promote airflow for sleepers who tend to feel warm at night. A firmer hybrid can offer a balanced feel: the coils keep the body lifted, while the upper layers soften contact around the shoulders and hips. For anyone who likes a particularly solid sleep surface, a two-sided or flippable design may offer different firmness levels on opposite sides, allowing the feel to be adjusted over time. Pay close attention to the mattress thickness as well. A taller profile may make getting in and out of bed more comfortable, but it can also require deep-pocket sheets and alter the finished height of the sleep setup. An 84-inch mattress may be especially useful in a spacious primary bedroom, a guest room intended for taller visitors or a home where a California King bed creates a more natural fit than a standard king. It can also be a thoughtful gift for someone moving into a larger home, upgrading a long-used mattress or setting up a welcoming guest space. Because a mattress is a personal purchase, gift-givers may want to involve the recipient in selecting the firmness, size and construction instead of choosing based on appearance alone.

Before purchasing, confirm the exact dimensions of the mattress, foundation, frame and available room. The 84-inch length needs enough clearance at both ends of the bed, including space for baseboards, nightstands and walkways. Measure the doorway, staircase and hallways as well, since a California King mattress is substantial even when compressed for delivery. Split California King mattresses can be easier to carry and position, and they may be a practical choice when two sleepers prefer different firmness levels or when an adjustable base is part of the setup. A split configuration can also reduce motion transfer between partners, although the center seam may be noticeable without properly fitted sheets or a mattress bridge. Check that the support system is compatible with the mattress and that the slats are properly spaced according to the manufacturer’s requirements. A firm mattress still needs an appropriate foundation to perform as intended; an unsuitable base can create uneven support, premature wear or warranty concerns. Bedding deserves similar attention. California King sheets are longer than standard king sheets, and Split California King setups may require two fitted sheets rather than one. Look for sheets labeled for the correct size and mattress depth, with enough stretch to stay in place when sleepers move during the night. A breathable protector can help shield the mattress from spills, dust and everyday wear without substantially changing its firm feel. During the cooler months, layering a light blanket or breathable comforter can create warmth without burying the supportive character of the mattress. If an 84-inch length is more than you need, comparing these options with Firm Height 75 Mattresses may help clarify which dimensions best suit your space and sleeping habits. With the right size, compatible base and carefully chosen comfort layers, a firm 84-inch mattress can create a spacious, steady place to rest night after night.

What makes a mattress firm? + -

A firm mattress has a more supportive feel with less give when you lie down. Its comfort comes from the combination of the comfort layers, support core and upholstery materials.

What types of materials are used in firm mattresses? + -

Firm mattresses may include materials such as innersprings, foam, memory foam, latex or a combination of these. Each material can create a different feel, from responsive and buoyant to contouring and pressure-relieving.

Are firm mattresses available in different comfort feels? + -

Yes. Firm mattresses can vary in feel depending on their construction. Some have a flatter, more supportive surface, while others include cushioning layers for a slightly more comfortable feel without losing firmness.

What type of foundation works with a firm mattress? + -

Many firm mattresses are compatible with a platform bed, adjustable base or traditional foundation. Always review the mattress manufacturer's recommendations to confirm which foundation types are suitable.

How can I care for a firm mattress? + -

Use a supportive foundation, rotate the mattress if the manufacturer recommends it and protect the surface with a breathable mattress protector. Follow the care instructions provided with your mattress for the best maintenance routine.