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Ashley Furniture
Low Profile Black King Foundation
Sale price $319.00 Regular price $799.00 60% OffUnit priceUnavailable -
HomElegance
Perrin Eastern King Mattress Foundation
Sale price $139.00 Regular price $399.00 65% OffUnit priceUnavailable -
Ashley Furniture
King Size Black Metal Foundation
Sale price $249.00 Regular price $629.00 60% OffUnit priceUnavailable -
Furniture of America
Sale price $139.00 Regular price $249.00 44% OffUnit priceUnavailable -
Coaster
Mercer Grey Split Eastern King Standard Box Spring Foundation
Sale price $319.00 Regular price $799.00 60% OffUnit priceUnavailable -
Furniture of America
Bird of paradise White Eastern King Foundation
Sale price $259.00 Regular price $569.00 54% OffUnit priceUnavailable -
Purple
Purple Low Profile 5" Gray King Flat Foundation
Sale price $530.00 Regular price $1,329.00 60% OffUnit priceUnavailable -
Purple
Purple Standard 9" Gray King Flat Foundation
Sale price $530.00 Regular price $1,329.00 60% OffUnit priceUnavailable -
Diamond Mattress
Geneva Versatile King Foundation
Sale price $295.00 Regular price $739.00 60% OffUnit priceUnavailable -
Coaster
Mercer Grey Low Profile Box Spring Foundation
Sale price $319.00 Regular price $799.00 60% OffUnit priceUnavailable -
Furniture of America
Aleksa Gray Eastern King Foundation
Sale price $269.00 Regular price $599.00 55% OffUnit priceUnavailable -
Furniture of America
Lilium White/Brown Eastern King Foundation
Sale price $259.00 Regular price $569.00 54% OffUnit priceUnavailable -
Ashley Furniture
Better than a Boxspring 2-Piece King Foundation (Split King)
Sale price $239.00 Regular price $599.00 60% OffUnit priceUnavailable
Do You Need a Box Spring for a King Bed?
It depends on your bed frame. King platform beds with built-in slat support do not require a separate foundation. Traditional king bed frames with perimeter rails and a center support beam are designed to hold a box spring. If your frame falls into this category, a king foundation is essential for proper mattress support. Without one, the mattress will sag between the rails and wear out prematurely.
Single King vs. Split King Box Spring
A single-piece king box spring is one solid 76" x 80" unit. While it provides a seamless support surface, it can be extremely difficult to move through narrow doorways, staircases, and hallways. A split king box spring divides the base into two 38" x 80" halves (Twin XL dimensions) that fit through standard doors with ease. Once placed on the frame, the two halves sit flush and perform identically to a single-piece base.
What Mattress Pairs with a King Foundation?
Any king-size mattress in memory foam, hybrid, innerspring, or latex works on a king foundation. For foam and hybrid models, choose a rigid foundation over a coil box spring to maintain the flat surface these mattresses need. Our king mattresses collection covers every comfort level and material type.
Choosing the Right Profile Height
King foundations come in low (4" to 5.5"), standard (7" to 7.5"), and high (9" to 9.5") profiles. Because king beds already sit high due to the thicker mattresses commonly used at this size, many shoppers opt for a low profile foundation to keep the total bed height manageable. For detailed comparisons, see our foundations by height collection.
King vs. California King: Checking Your Size
Make sure you are ordering the right size. A king foundation is 76" x 80" (wider), while a California King foundation is 72" x 84" (longer). The two are not interchangeable. If your mattress is a California King, visit our Cal King foundations page instead.
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