Cyber Monday Sale On King Size Mattresses

Shop king size mattresses for Cyber Monday with your comfort preferences and budget in mind. Compare prices, mattress descriptions and listed features across the selection below, then check dimensions to find an option that fits your bed frame and bedroom.

Sleepy's Basic Innerspring Firm Mattress

8758

Starting at

$249⁹⁹

Firm Comfort, best for

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

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

Serta Perfect Sleeper Sleep Excellence Medium PillowTop Mattress

1467

Starting at

$1999⁹⁹

Medium Comfort, best for

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

FREE ADJUSTABLE BASE ³ with code ELEVATE

Tempur-Pedic TEMPUR-Adapt 11" Medium Previous Generation Mattress

3710

Starting at

$2029⁷⁷

$2899⁰⁰

$869 OFF

Medium Comfort, best for

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

Stearns & Foster Estate 14.5" Firm Mattress

1865

Starting at

$2899⁰⁰

$3099⁰⁰

$200 OFF

Firm Comfort, best for

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

$300 Instant Gift⁴ with purchase of a mattress set.

Sealy Essentials Sudley 8.5" Firm Mattress

989

Starting at

$499⁷⁷

$999⁹⁹

$500 OFF

Firm Comfort, best for

Back, Stomach Sleepers
Pain
Temperature
Bed Partner
Toss and Turn

Purple Original Mattress

59815

Starting at

$1899⁰⁰

$2199⁰⁰

$300 OFF

Medium Comfort, best for

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

Sleepy's By Sealy Slumber Cushion Firm Mattress

309

Starting at

$1999⁹⁹

Medium Comfort, best for

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

FREE ADJUSTABLE BASE ³ with code ELEVATE

Stearns & Foster Lux Estate Elite 16" Medium Euro Pillow Top Mattress

1017

Starting at

$4299⁰⁰

$4699⁰⁰

$400 OFF

Medium Comfort, best for

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

$300 Instant Gift⁴ with purchase of a mattress set.

Sleepy's By Sealy Slumber Medium Mattress

196

Starting at

$709⁹⁹

$2299⁹⁹

$1590 OFF

Medium Comfort, best for

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

FREE ADJUSTABLE BASE ³ with code ELEVATE

Tulo Bamboo 6" Firm Green Tea Memory Foam Mattress

5604

Starting at

$259⁹⁹

$729⁹⁹

$470 OFF

Firm Comfort, best for

Back, Stomach Sleepers
Pain
Bed Partner
Temperature
Toss and Turn

Nectar Premier 13" Medium Memory Foam Mattress

580

Starting at

$1099⁰⁰

$1799⁰⁰

$700 OFF

Medium Comfort, best for

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

Nectar Classic 12" Firm Memory Foam Mattress

245

Starting at

$899⁰⁰

$1399⁰⁰

$500 OFF

Firm Comfort, best for

Back, Stomach Sleepers
Pain
Bed Partner
Temperature
Toss and Turn

Nectar Luxe 14" Medium Memory Foam Mattress

240

Starting at

$1649⁰⁰

$2249⁰⁰

$600 OFF

Medium Comfort, best for

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

Sealy Essentials Spruce 5.5" Firm Mattress

1373

Starting at

$549⁹⁹

$949⁹⁹

$400 OFF

Firm Comfort, best for

Back, Stomach Sleepers
Pain
Temperature
Bed Partner
Toss and Turn

Beautyrest Black Series Two 16.25" Plush Pillow Top Mattress

301

Starting at

$3699⁰⁰

$4099⁰⁰

$400 OFF

Plush Comfort, best for

Side Sleepers
Pain
Bed Partner
Temperature
Toss and Turn

$300 ⁶ adjustable base instant gift with purchase.

Cyber Monday is a great time to compare king size mattresses at Mattress Firm and focus on the features that matter most to your nightly comfort. A standard king mattress measures 76 inches wide by 80 inches long, giving you 16 more inches of width than a queen mattress—a helpful difference for couples who want more room to stretch out. As you explore king mattresses for Cyber Monday, consider how mattress materials work with your preferred sleep position. Memory foam contours to your body and can help limit motion transfer, while innerspring mattresses typically offer a more responsive feel. Hybrid mattresses combine coils with comfort layers made from materials such as foam or latex, though their feel varies by construction. Side sleepers may appreciate cushioning around the shoulders and hips, while back and stomach sleepers may prefer a firmer surface. The right balance of cushioning and support depends on your body, preferences and sleeping habits. Finding a king size mattress on Cyber Monday also means looking beyond the mattress price to make sure your choice fits your bedroom and setup. Measure your room, doorways and stairways before ordering, and leave enough space around the bed to move comfortably. If length matters more than width, compare a standard king with a California King mattress, which measures 72 inches wide by 84 inches long. For partners interested in separate adjustable positioning, a split king pairs two Twin XL mattresses with a compatible adjustable base; confirm that both the mattresses and base support your intended setup. Compare product details for motion isolation, edge support and temperature-regulating materials rather than relying on firmness labels alone. Before completing your Cyber Monday king mattress purchase, review the current price, delivery availability, applicable trial terms and warranty information. Include any needed foundation, mattress protector and correctly sized bedding in your budget so you can choose a sleep setup that fits your comfort needs and spending plans.

How can I compare mattresses online during Cyber Monday? + -

When browsing king mattresses on Cyber Monday, compare construction, materials, firmness descriptions and surface styles. Read product details alongside customer reviews, keeping in mind that descriptions of comfort reflect personal preferences.

What is the difference between memory foam, innerspring and hybrid mattresses? + -

Memory foam mattresses use foam layers without a coil core. Innerspring mattresses feature a coil core beneath upholstery layers. Hybrid mattresses combine a coil core with substantial layers of foam, latex or other cushioning materials.

What do mattress firmness labels mean? + -

Labels such as plush, medium and firm describe how soft or firm a mattress feels. These descriptions can vary by manufacturer, so compare the firmness label with details about the cushioning layers and overall construction.

How does a pillow top differ from a Euro top? + -

A pillow top has an added cushioning layer with a visible separation from the mattress beneath it. A Euro top has cushioning sewn flush with the mattress edges for a more uniform appearance. Either style can come in different firmness levels.

How should I care for a new mattress? + -

Start with the manufacturer's care instructions, including guidance on cleaning and rotation. Use a mattress protector and wash bedding regularly. Rotate or flip the mattress only as directed, since care requirements vary by construction.