A king mattress is 76 inches wide by 80 inches long, giving you 6,080 square inches of sleep surface. That's 16 inches wider than a queen, which translates to real, noticeable space when you're sharing a bed.
Here's everything you need to know before buying one.
Quick Navigation
- King Mattress Dimensions
- King vs. California King
- Room Size Requirements
- Who It's Best For
- Buying Tips
- FAQ
King Mattress Dimensions
The standard king mattress, also called an Eastern King, measures:
- Width: 76 inches (6 feet 4 inches)
- Length: 80 inches (6 feet 8 inches)
- Height: Varies by model, typically 10–15 inches
For reference, a queen is 60" x 80". The king adds 16 full inches of width, enough that two adults can sleep comfortably without crowding each other, even if one or both move around at night.
King vs. California King: Which One Is Right for You?
| Dimension | Standard King (Eastern King) | California King |
|---|---|---|
| Width | 76 inches | 72 inches |
| Length | 80 inches | 84 inches |
| Best For | Couples who want more width | Taller sleepers (6'2" and above) |
| Room Fit | Square rooms work well | Better for longer, narrower rooms |
The California King trades 4 inches of width for 4 inches of extra length. If you or your partner is over 6'2", the Cal King is worth considering. For most couples, the standard king provides more usable space.
Room Size Requirements
A king mattress needs a bedroom that can comfortably fit it, and still leave room to walk around, open drawers, and not feel cramped.
- Minimum room size for a king: 12 x 12 feet (gives about 2 feet of clearance on each side)
- Comfortable room size: 13 x 13 feet or larger
- Ideal room size: 14 x 16 feet if you want nightstands, a dresser, and walking space
Before buying, measure your room and mark out the mattress footprint on the floor with tape. It's a simple step that prevents a frustrating return.
Who a King Mattress Is Best For
Great choice if you are:
- A couple who want maximum personal sleeping space
- A light sleeper sharing a bed, more space means less disruption
- A parent who co-sleeps with young children or pets
- Someone who sprawls out or sleeps with multiple pillows
- Moving into a larger bedroom and upgrading your sleep setup
May not be the best fit if you:
- Have a bedroom smaller than 12 x 10 feet
- Live alone and don't need the extra width
- Frequently move and want a more manageable mattress to transport
- Are tall (6'2"+), a California King gives you more legroom
What to Look for When Buying a King Mattress
Firmness
Firmness comes down to your sleep position and body type. Side sleepers generally do best with medium to medium-soft. Back sleepers typically prefer medium-firm. Stomach sleepers usually need firm support to avoid lower back strain.
Mattress Type
King mattresses are available in every major construction type:
- Memory foam, great pressure relief, good motion isolation
- Hybrid, combines coil support with foam comfort layers; most popular for couples
- Latex, responsive, durable, naturally cooling
- Innerspring, traditional feel, very breathable
Motion Isolation
If one partner moves frequently, look for a mattress with good motion isolation, typically memory foam or foam-topped hybrids. Pocketed coil systems also perform well here.
Edge Support
On a king, edge support matters. Strong edges mean you can use the full surface of the mattress without feeling like you'll roll off. This is especially important for couples who sleep near the edges.
Budget
King mattresses typically cost 20–30% more than queen mattresses of the same model. That's expected given the added materials. Financing options are available at LA Mattress Store if you want to spread the cost over time.
Try Before You Buy
The best way to choose a king mattress is to lie on it. Visit any of our LA Mattress Store locations and spend a few minutes on each model you're considering. Our sleep experts can help you compare firmness levels, construction types, and narrow down the right fit for how you actually sleep.
We also offer a 120-night comfort guarantee, so if the mattress doesn't work for you at home, you're not stuck with it.
Frequently Asked Questions
What are the exact dimensions of a king mattress?
A standard king (Eastern King) mattress is 76 inches wide by 80 inches long. Height varies by mattress model, typically between 10 and 15 inches.
What's the difference between a king and a California king?
A standard king is 76" x 80". A California king is 72" x 84", narrower but 4 inches longer. The Cal King suits tall sleepers; the standard king gives more width for couples.
What room size do I need for a king bed?
A minimum of 12 x 12 feet is recommended. A 13 x 13 or larger room gives you more comfortable clearance around the bed.
Is a king mattress too big for one person?
Not necessarily. If you like a lot of space, sleep restlessly, or have pets, a king can be great for solo sleepers. That said, a queen is usually sufficient for one person and easier to fit in smaller rooms.
Do king beds need a special bed frame?
Yes, king mattresses require a king-size bed frame. Most king frames also include a center support leg to prevent sagging in the middle. Make sure any frame you buy is designed for a 76" x 80" mattress.
Are king and California king bedding the same?
No. King and California king sheets and comforters are sized differently. Always check the label before buying bedding. Cal King bedding is longer and narrower than standard king.
How much does a king mattress cost?
King mattress prices range widely, from around $500 for a basic model to $3,000+ for premium options. At LA Mattress Store, we carry king mattresses at a range of price points, and financing is available.
Related reading
- Our complete mattress size guide
- Compare to Queen (the smaller option)
- Queen vs King, head-to-head comparison
- King vs California King, which is right for you
King size mattress at a glance, quick reference
A king bed (also called an Eastern king or standard king) measures 76 × 80 inches. Here's a quick reference covering the most-searched king mattress dimension questions:
| Measurement | Value |
|---|---|
| Width | 76 inches (6'4" / 193 cm) |
| Length | 80 inches (6'8" / 203 cm) |
| Surface area | 6,080 sq in (3.92 m²) |
| Per-person width (couple) | ~38 inches each (same as a Twin XL) |
| Minimum recommended room | 12 × 12 ft |
| vs Queen (60" × 80") | +16" wider, same length |
| vs California King (72" × 84") | 4" wider, 4" shorter |
| Also called | Eastern King, Standard King |
How big is a king size mattress? 76 inches wide by 80 inches long. In feet, that's 6'4" × 6'8". In centimeters, 193 × 203 cm.
Is a king mattress big enough for two adults? Yes, each person gets roughly 38 inches of sleep width, which is the same as a Twin XL. That's why couples who upgrade from queen to king consistently report a noticeable improvement in shared-sleep quality.
King vs California king dimensions: Standard king is wider (76" vs 72"). California king is longer (84" vs 80"). Surface area is nearly identical. Choose California king only if you're 6'2" or taller, or your room is long and narrow.
For the full size lineup and a side-by-side bed size chart, see our mattress size comparison page. Shop king mattresses · California king mattresses · adjustable bases for split king setups.
