How Long Is a King Mattress? Standard Lengths, Variations, and What to Expect
If you’re asking “How long is a king mattress?”, you’re likely measuring a bedroom, buying new bedding, or comparing sizes. King mattresses are popular for their width, but the length matters just as much for comfort and room layout.
Below, you’ll find clear answers about standard king mattress lengths, common variations, and how to know which size is right for you.
What Is the Standard Length of a King Mattress?
In most places that use imperial measurements, a standard king mattress (often called an Eastern king) typically measures:
- 76 inches wide x 80 inches long
- Approximately 193 cm x 203 cm
So when you see “king size mattress,” this 80-inch length is usually what’s meant.
This length is the same as a standard queen mattress, but a king gives more width. That means there is more room side-to-side, but not extra inches for height compared with a queen.
Are There Different Types of King Mattress Lengths?
Yes. When people ask “How long is a king mattress?”, they may be thinking of different king variations. The most common include:
| Mattress Type | Width x Length (Approx.) | Typical Use |
|---|---|---|
| Standard King | 76" x 80" (193 x 203 cm) | Couples wanting more elbow room |
| California King | 72" x 84" (183 x 213 cm) | Taller sleepers, longer rooms |
| Split King | Two 38" x 80" (97 x 203 cm) | Adjustable bases, different firmness |
How long is a California king mattress?
A California king is typically 84 inches long, or about 213 cm.
It is longer but slightly narrower than a standard king:
- California king: 72" x 84"
- Standard king: 76" x 80"
This extra length can feel more comfortable for taller sleepers or for those who prefer extra foot room.
How long is a split king mattress?
A split king is usually made of two twin XL mattresses, each measuring:
- 38 inches wide x 80 inches long, or about 97 cm x 203 cm
Side by side, they form the same overall size as a standard king:
- 76 inches wide x 80 inches long
The length of each half is still 80 inches, so a split king does not add extra length; it only changes how the mattress is constructed.
Why Does King Mattress Length Matter?
Knowing how long a king mattress is is important for several reasons:
- Room layout: An 80" or 84" length takes up a noticeable portion of the room. It affects where you can place dressers, nightstands, and walking space.
- Sleeper height: Taller sleepers often feel more comfortable with extra legroom. Some prefer a California king for this reason.
- Bedding fit: Sheets, mattress protectors, and bed frames are sized for specific lengths. Using the wrong size can lead to poor fit or bunching.
- Frame and headboard sizing: Bed frames and headboards are built for specific mattress dimensions. A mismatch can leave gaps or overhangs.
Common Questions About King Mattress Length
Is a king mattress long enough for tall people?
For many sleepers, the 80-inch length of a standard king is comfortable. Taller sleepers—especially those over average height—may prefer the 84-inch length of a California king, as it offers a bit more legroom at the foot of the bed.
Do all king mattresses have the same length?
Not always. The exact length of a “king” mattress can vary by:
- Type: Standard king vs. California king vs. regional variations
- Region: Some countries use slightly different standard sizes
- Manufacturer: Dimensions can vary by an inch or so depending on construction and materials
Because of this, it is helpful to check the listed measurements instead of relying only on the word “king.”
How do I know if a king mattress will fit in my room?
To see if your room can comfortably fit a king mattress:
- Measure the available floor space where the bed will go.
- Allow for the mattress length (80" or 84") plus extra space around the bed—often at least 24"–30" of walking room on the open sides.
- Consider additional furniture, such as nightstands or a bench at the foot of the bed.
What Should I Consider Before Choosing a King Length?
When deciding between king sizes and their lengths, consider:
- Your height and sleep position:
Back or stomach sleepers may notice mattress length more than curl-up side sleepers. - Room shape:
Longer, narrower rooms may work better with a California king, while wider rooms often suit a standard king. - Existing bedding and frames:
Standard king and California king use different sheets and frames, so switching between them may require new accessories. - Who is using the bed:
Couples, co-sleeping with children, or people who move a lot at night may prioritize width, length, or both.
✔️ Quick Mattress Takeaways
Key points consumers should understand about “How Long Is a King Mattress”:
- A standard king mattress is typically 76" x 80" (193 x 203 cm).
- A California king mattress is usually 72" x 84" (183 x 213 cm)—longer but narrower than a standard king.
- A split king combines two twin XLs, each 38" x 80", for the same overall size as a standard king.
- Not all kings are the same length—always check the exact measurements.
- Consider room size, sleeper height, bedding, and bed frames when choosing a king mattress length.
Understanding how long a king mattress is—and which version you’re looking at—helps you plan your space, pick the right bedding, and choose a size that feels comfortable for your needs.
