How Many Inches Is a King Mattress? Exact Dimensions and FAQs
If you’re asking “How Many Inches Is a King Mattress”, you’re likely trying to figure out whether it will fit your room, bed frame, or bedding. This guide explains the standard king size in inches, how it compares to other sizes, and what else you should consider before choosing one.
What Are the Standard Dimensions of a King Mattress?
In most cases, a standard king mattress is 76 inches wide and 80 inches long.
- Width: 76 inches
- Length: 80 inches
This size is sometimes called an “Eastern King” and is the most common king option in many regions.
Because the question “How Many Inches Is a King Mattress” can also refer to thickness, it helps to separate length/width from height:
- Standard king length & width: 76" x 80"
- Typical thickness range: about 8"–14", depending on the model and construction
There is no single universal height for king mattresses; thickness varies by design and materials.
Why Do the Inches of a King Mattress Matter?
Understanding how many inches is a king mattress matters for a few practical reasons:
- Room fit: You need enough floor space to walk around the bed and place furniture.
- Bed frame compatibility: Frames, bases, and foundations are built to specific dimensions.
- Bedding sizing: Sheets, protectors, and toppers must match both the surface size and often the thickness.
- Sleeping space: The width and length determine how much personal space each sleeper has.
For couples, a king mattress often provides more individual space than smaller mattress sizes, which many people find helpful for minimizing disturbances.
Are All King Mattresses the Same Size?
Not always. While 76" x 80" is the common standard, there are variations of king sizes that can cause confusion.
Common King Variations (Approximate)
| Mattress Type | Width (inches) | Length (inches) |
|---|---|---|
| Standard King | 76" | 80" |
| California King | 72" | 84" |
| Split King | 76" | 80" (two 38"x80") |
- California king: Slightly narrower and longer than a standard king.
- Split king: Made of two twin XL mattresses side by side, creating a king-sized surface.
When you see the term “king,” it usually means standard king, but it is helpful to check the exact measurements in inches before choosing bedding or bases.
How Thick Is a King Mattress?
If you are asking “How many inches is a king mattress?” and thinking about thickness, here’s what to know:
- Many king mattresses fall in the range of 10"–14" thick.
- Some budget or lower-profile models may be around 8"–10".
- Some luxury or extra-plush models may be 14" or more.
Why thickness matters:
- Sheet fit: Fitted sheets list a “pocket depth” that needs to match or exceed the mattress height.
- Bed height: The combination of mattress + foundation or base affects how easy it is to get in and out of bed.
- Edge support and feel: Thickness can influence how a mattress feels at the edges and when you move around, although materials and construction also play a large role.
Will a King Mattress Fit in My Bedroom?
To decide whether a king mattress will fit, start with its footprint of 76" x 80", then add space for walking and furniture.
A simple way to think about it:
- Allow at least 2 feet of clearance on the sides and foot of the bed for comfortable movement.
- Consider doors, closets, and windows so the bed does not block access or airflow.
- Remember that headboards and frames add extra inches to the total footprint.
Measuring your space before deciding on a king can help avoid feeling crowded or having to reposition other furniture.
Do I Need Special Bedding for a King Mattress?
Yes, you will usually want bedding labeled specifically for “King” size:
- Fitted sheet: Sized for ~76" x 80" and must match the mattress thickness (check pocket depth).
- Flat sheet and comforter/duvet: Sized larger than the mattress to allow for drape.
- Mattress protector or topper: Must match the king dimensions and thickness to stay secure.
If you have a California king instead of a standard king, you will need bedding specifically labeled for that size due to the different dimensions.
✔️ Quick Mattress Takeaways
Key points consumers should understand about How Many Inches Is a King Mattress:
- A standard king mattress is 76 inches wide and 80 inches long.
- There is no single standard thickness, but many king mattresses are around 10"–14" high.
- California king is different: typically 72" x 84" (narrower and longer).
- Split king uses two twin XL mattresses (about 38" x 80" each) to form a king-sized surface.
- Always check exact dimensions in inches before buying a frame, bedding, or topper.
- Measure your bedroom to be sure a 76" x 80" footprint plus walking space will fit comfortably.
Understanding how many inches is a king mattress—in both surface size and thickness—makes it easier to plan your space, pair it with the right accessories, and choose the version of “king” that suits your needs.
