What Are Dimensions Of King Size Mattress? Standard Measurements & FAQs

If you’re asking “What Are Dimensions Of King Size Mattress”, you’re likely trying to figure out if a king bed will fit your bedroom, your bed frame, or your lifestyle. This guide explains the standard king size mattress dimensions, how they compare to other sizes, and what to keep in mind before choosing one.

What Are Dimensions Of King Size Mattress in Inches and Centimeters?

In most regions that follow US/standard sizing, the standard king size mattress measures:

• 76 inches wide x 80 inches long
• Approximately 193 cm wide x 203 cm long

This size is often called an “Eastern King.” It is wider than a queen but the same length.

Are There Different Types of King Size Mattresses?

Yes. When people search “What Are Dimensions Of King Size Mattress”, they are sometimes surprised to learn that “king” can mean different things depending on the style and region.

Here are the most common king-related sizes in the US/standard system:

How is a King Different from a California King?

• King (Eastern King):

  • Wider: 76" wide
  • Shorter: 80" long
  • Often preferred by couples who want maximum side-to-side space.

• California King:

  • Narrower: 72" wide
  • Longer: 84" long
  • Often chosen by taller sleepers who want extra foot room.

What Is a Split King?

A split king uses two separate twin XL mattresses side by side:

• Each half: 38" x 80"
• Together: Same footprint as a 76" x 80" king

This option can help when:

• Couples prefer different firmness levels
• You’re using an adjustable base where each side moves independently
• Narrow hallways or staircases make a one-piece king mattress hard to move

Why Do King Size Mattress Dimensions Matter?

Understanding What Are Dimensions Of King Size Mattress matters for several practical reasons:

• Room fit: A king mattress is large. You’ll want enough walking space and room for furniture.
• Bedding and accessories: Sheets, protectors, and toppers must match the exact size (king vs. California king vs. queen).
• Bed frame compatibility: Not all frames fit every “king.” Some are sized only for standard king, others for California king.
• Movement and delivery: A king is bulky. Measuring doorways, hallways, and stairs can prevent delivery issues.

A common recommendation is to allow space on both sides and at the foot of the bed so the room doesn’t feel cramped.

How Does a King Compare to a Queen or Full?

Many shoppers ask about “What Are Dimensions Of King Size Mattress” in comparison to other popular sizes.

• Full (Double): About 54" x 75"
• Queen: About 60" x 80"
• King: About 76" x 80"

Compared with a queen, a king has:

• The same length (80")
• 16 extra inches of width overall

This added width can be especially useful if:

• Two adults share the bed and want more personal sleeping space
• A child or pet sometimes joins in

What Should I Consider Before Buying a King Size Mattress?

When thinking about a king, it helps to look beyond just “What Are Dimensions Of King Size Mattress” and consider your overall setup.

Key considerations:

• Bedroom size:

  • A king can dominate a small room.
  • Many people prefer to have enough space for nightstands, dressers, and clear walking paths.

• Bed frame & base:

  • Confirm the frame is made for a standard king (76" x 80") or another variation.
  • Some adjustable or platform bases are size-specific.

• Bedding & accessories:

  • Look for bedding labeled clearly as “King” or “California King” so it matches your mattress.

• Doorways and stairs:

  • Measure tight corners and door frames.
  • A split king can be easier to move than one large king mattress.

✅ Quick Mattress Takeaways

Key points to remember about “What Are Dimensions Of King Size Mattress”:

• Standard King Size Dimensions:

  • 76" x 80" (about 193 x 203 cm)

• Common Variations:

  • California King: 72" x 84" (narrower, longer)
  • Split King: Two 38" x 80" mattresses creating a 76" x 80" sleeping surface

• Compared to Queen:

  • Same length (80")
  • 16" wider, giving more space for couples

• Room Planning Tips:

  • Check bedroom dimensions, leaving walking space
  • Match mattress size precisely with bed frame and bedding
  • Consider delivery paths through doors, hallways, and stairs

Understanding What Are Dimensions Of King Size Mattress—and how those dimensions affect your room, frame, and bedding—helps you choose a size that feels comfortable in both your sleeping space and your living space.