How Long Is a King Size Mattress? Length, Variations, and What to Expect
If you’re wondering “How long is a king size mattress?”, you’re usually trying to figure out if it will fit your bedroom, your bed frame, or your height. This guide walks through standard king mattress lengths, common variations, and what those measurements mean in everyday use.
What Is the Standard Length of a King Size Mattress?
In most cases, a standard king size mattress measures:
- 76 inches wide x 80 inches long
- Approximately 193 cm x 203 cm
So, when you ask “How long is a king size mattress?”, the usual answer is 80 inches (about 203 cm).
This size is often called a “king” or “Eastern king.” It offers the same length as a standard queen, but with extra width for more elbow room.
Are There Different Types of King Size Mattresses?
Yes. Not every king mattress is the same length. Here are the most common king variants by size:
| Mattress Type | Width x Length (inches) | Typical Name |
|---|---|---|
| Standard King | 76" x 80" | King / Eastern King |
| California King | 72" x 84" | Cal King |
| Split King | 76" x 80" (2 x 38" x 80") | Split King |
How long is a king size mattress vs a California king?
- Standard king: 80 inches long
- California king: 84 inches long
A California king is longer but slightly narrower, which can be important for taller sleepers or narrow rooms.
What about a split king?
A split king uses two twin XL mattresses, each measuring 38" x 80", placed side by side.
The overall length is still 80 inches, just like a regular king. The main difference is the split down the middle, not the size.
Why Does Mattress Length Matter?
Understanding how long a king size mattress is helps with:
- Room layout: A king can dominate a smaller bedroom. Knowing it’s 80 inches long helps you plan walking space, nightstands, and other furniture.
- Sleeper height: Taller sleepers may feel cramped on shorter mattresses. Some prefer the extra 4 inches of a California king.
- Bedding fit: Sheets, mattress protectors, and bed frames are sized for specific dimensions. Using the wrong size can lead to loose or overly tight bedding.
- Doorways and hallways: Long mattresses can be awkward to move. Knowing the exact length helps you plan the path to your bedroom.
Do King Mattress Dimensions Ever Vary?
While 76" x 80" is widely accepted as the standard, there can be minor variations:
- Some manufacturers round up or down slightly.
- Measuring foam or hybrid mattresses can show small differences depending on how the materials settle.
- Pillow tops and thick comfort layers can add to the perceived height, but they do not change the official length.
If exact fit is crucial—for example, for a custom bed frame—checking the listed dimensions for a specific model is helpful.
How Much Space Does a King Mattress Take Up in a Room?
Because a king mattress is 76 inches wide and 80 inches long, it’s useful to compare that to your room size.
A common rule of thumb is to allow space to walk comfortably around the bed. Many people like at least:
- Around 2–3 feet of open space on the sides
- Some clear space at the foot of the bed for walking or storage
This isn’t a strict rule, just a practical guideline to help decide whether a king (80 inches long) makes sense for your space.
Is a King Mattress Long Enough for Tall Sleepers?
For many people, 80 inches (about 6 feet 8 inches) is plenty of length. However:
- Taller sleepers who like to stretch out fully or sleep near the edge of the bed may notice their feet getting close to the end.
- A California king, at 84 inches long, can feel more comfortable for those who value extra legroom.
Position, pillow size, and how you sleep (curled vs stretched) also affect how much length you actually use.
✔️ Quick Mattress Takeaways
Key points to understand about “How Long Is a King Size Mattress”:
- Standard king length: A king size mattress is 80 inches long (about 203 cm).
- Standard king size: 76" x 80" (193 cm x 203 cm).
- California king: Slightly longer at 72" x 84", offering more legroom.
- Split king: Still 80 inches long overall, made from two twin XL mattresses.
- Room fit: Always measure your space to ensure you have room to walk around the 80-inch length.
- Height considerations: Very tall sleepers sometimes prefer the 84-inch length of a California king.
- Small variations: Actual dimensions can vary slightly by manufacturer, so checking exact measurements can be useful.
Understanding how long a king size mattress is makes it easier to plan your bedroom layout, choose the right bed frame, and decide whether a standard king or a longer option like a California king better suits your needs. With the typical king length of 80 inches, you have a clear starting point for comparing sizes and ensuring a comfortable, practical setup.
