Somewhere around 2 a.m., a partner's elbow lands in your ribs again, and the dog has claimed the middle of the bed like it pays rent. Moving up to a king feels like the obvious fix. Then comes the worry that a giant new mattress will swallow the room or barely clear the dresser. Knowing the exact king size mattress dimensions before you shop is the simplest way to get the extra space without the regret.
Consider the measuring tape already handled. Our mattress team at Spencer's TV & Appliance has pulled together every number you need in one place. This guide covers exact king measurements in inches, feet and centimeters, the difference between king, California king and split king, and a full size chart. You will also learn how big your bedroom should be, how frames and bedding change the math, how to plan delivery day, and which king mattresses we recommend.
Key Takeaways
- A standard king is 76 by 80 inches: That equals 6 feet 4 inches by 6 feet 8 inches, or about 193 by 203 centimeters.
- Each sleeper gets 38 inches: That is the same width as a twin XL, and 8 inches more per person than a queen.
- California king is longer, not bigger: At 72 by 84 inches, it trades 4 inches of width for 4 inches of length.
- Measure the room and the frame: Plan for a room of at least 12 by 12 feet and account for the full bed frame footprint.
Find the King Mattress That Fits Your Bedroom
Compare king mattresses in person with help from a local Phoenix-area team. Spencer's TV & Appliance offers expert guidance plus delivery and setup across the Valley.
King Size Mattress Dimensions in Inches, Feet and Centimeters
A standard king mattress measures 76 inches wide by 80 inches long. That is 6 feet 4 inches wide by 6 feet 8 inches long, or about 193 by 203 centimeters. It is the widest standard mattress size sold in the United States.
Surface Area and Personal Space
A king gives you about 6,080 square inches of sleep space, or roughly 42 square feet. Split down the middle, each sleeper gets 38 inches of width. That is the same width as a twin XL mattress, so it feels like each person has a bed of their own.
Mattress Height
King size bed dimensions also include height, which changes a lot from one model to the next.
- Low-profile: About 8 to 10 inches, common in foam and guest mattresses.
- Standard: About 10 to 14 inches, the most common range.
- Pillow top and luxury hybrid: About 14 to 18 inches or more, with extra comfort layers on top.
Eastern King and Standard King
Eastern king and standard king are two names for the same 76 by 80 inch size. The word Eastern simply sets it apart from the California king.
Why Spec Sheets Matter
Real mattresses can measure slightly smaller than the standard size. Foam layers, quilting and coil systems leave small tolerances. For example, several of the Beautyrest king mattresses we carry list a length of 79.5 inches instead of a full 80. That half inch rarely matters in daily use, but it is worth checking the spec sheet if you are fitting a mattress into a tight frame or a built-in platform.
King vs California King vs Split King: Key Differences
The word king covers a few different sizes. Each one solves a different problem.
Standard King
The standard king is the best pick for couples who want the most width, families who share the bed with kids or pets, and most square or wide bedrooms.
California King
California king dimensions are 72 by 84 inches. It is 4 inches narrower and 4 inches longer than a standard king. That extra length makes it a strong choice for sleepers over 6 feet tall and for long, narrow rooms.
Here is the part most guides skip. A standard king has about 6,080 square inches of surface area, and a California king has about 6,048. They are nearly the same size overall, so the choice between king vs California king is really about shape, not total space.
Split King
A split king mattress is two twin XL mattresses, each 38 by 80 inches, placed side by side. Together they match the 76 by 80 inch footprint of a standard king. Split kings work best with adjustable bases, since each side can raise and lower on its own. They are also great for couples who want different firmness levels.
Oversized Kings
A few larger sizes exist, but they are hard to find and need custom bedding.
- Texas king: About 80 by 98 inches.
- Wyoming king: About 84 by 84 inches.
- Alaskan king: About 108 by 108 inches.
Read More: California King Mattress Size Guide: Is It Right for Your Bedroom? | Best King Mattresses for Couples, Back Pain, & Hot Sleepers
Mattress Size Chart: King Compared to Every Standard Size
Use this chart to compare every standard mattress size at a glance. Room sizes are general guidelines, so always measure your own space.
| Size | Inches (Centimeters) | Surface Area | Width per Sleeper | Minimum Room | Best For |
|---|---|---|---|---|---|
| Twin | 38 x 75 (97 x 191) | 2,850 sq. in. | 38 in. for one | 7 x 10 ft. | Kids and bunk beds |
| Twin XL | 38 x 80 (97 x 203) | 3,040 sq. in. | 38 in. for one | 7 x 10 ft. | Taller teens and dorms |
| Full | 54 x 75 (137 x 191) | 4,050 sq. in. | 27 in. each | 10 x 10 ft. | Single adults |
| Queen | 60 x 80 (152 x 203) | 4,800 sq. in. | 30 in. each | 10 x 10 ft. | Couples in average rooms |
| King | 76 x 80 (193 x 203) | 6,080 sq. in. | 38 in. each | 12 x 12 ft. | Couples, kids and pets |
| California King | 72 x 84 (183 x 213) | 6,048 sq. in. | 36 in. each | 12 x 12 ft. | Tall sleepers |
| Split King | Two 38 x 80 (97 x 203) | 6,080 sq. in. | 38 in. each | 12 x 12 ft. | Adjustable bases |
The biggest jump on the chart is from queen to king, which adds 16 inches of width while keeping the same 80-inch length.
What Size Bedroom Do You Need for a King Bed?
The commonly cited minimum bedroom size for a king bed is about 12 by 12 feet. A room that is 13 by 13 feet or larger feels much more comfortable once you add nightstands and a dresser.
Clearance to Plan For
- Walkways: Leave 24 to 36 inches on both sides and at the foot of the bed.
- Nightstands: Most need 18 to 24 inches of width on each side.
- Dressers: Leave room for drawers to open fully, often about 30 inches in front.
- Doors: Make sure the bedroom door and closet doors swing open without hitting the bed.
Map It Out With Painter's Tape
Before you buy, mark the full king bed footprint on the floor with painter's tape. Use the frame size, not just the mattress size. Walk around it, open the closet and pull out the dresser drawers. If anything feels tight, you will know before delivery day.
A Layout Tip for Phoenix-Area Homes
Many Valley homes, especially newer single-story builds, have primary suites with plenty of room for a king and a sitting area. Place the headboard on the longest solid wall, away from the door and any sliding patio door. Smaller secondary bedrooms, often around 10 by 11 feet, usually work better with a queen, which leaves enough floor space for a guest to move around.
King Bed Frame and Foundation Dimensions Explained
The mattress is only part of the footprint. King bed frame dimensions are almost always larger than 76 by 80 inches.
How Frames Add Size
- Basic metal frames: Add little to the mattress size.
- Platform beds: Often add a few inches on each side.
- Headboards and footboards: Can add several inches to the total length.
- Storage beds and sleigh beds: Can add 6 inches or more, plus room for drawers to open.
Support Systems for a King
Your support options include:
- Box spring or foundation: Usually two split pieces for a king, which makes them easier to carry.
- Platform bed: Built-in slats or a solid deck replace the foundation.
- Adjustable base: Raises the head and feet, and works with adjustable-compatible mattresses.
Any king frame should include center support legs. Without them, the middle can sag over time and may affect your mattress warranty.
Total Bed Height
A 16-inch pillow top on a tall foundation and frame can put the sleep surface well above knee height. Most adults find it easiest to get in and out when their feet rest flat on the floor while sitting on the edge.
Read More: Why Your Mattress Needs a Foundation: 3 Benefits Explained | Best Adjustable Beds for Better Sleep and Comfort
King Size Mattress Dimensions Pros and Cons
The extra width of a king is a big upgrade for most couples. It also asks more of your room, your budget and your moving crew.
Pros
More personal space
Each sleeper gets 38 inches, the same as a twin XL.
Better for couples
Less disturbance when one partner tosses, turns or gets up early.
Room for pets and kids
Morning snuggles and a dog at the foot of the bed fit without crowding.
Flexible setup
A split king option works with adjustable bases and dual comfort levels.
Cons
Needs a bigger room
A king works best in bedrooms of 12 by 12 feet or more.
Higher bedding cost
King sheets, comforters and frames cost more than queen sizes.
Harder to move
Its size and weight make stairs and tight turns a challenge.
King Size Sheets and Bedding Dimensions
King bedding has to match the mattress size and its height.
Typical King Bedding Sizes
- Fitted sheet: 76 by 80 inches, with a pocket depth to match your mattress height.
- Flat sheet: About 108 by 102 inches.
- Comforter or duvet: About 104 to 110 inches wide by 88 to 96 inches long.
- King pillowcase: About 20 by 40 inches, made for 20 by 36 inch king pillows.
Pocket Depth
Pocket depth is how tall the sides of a fitted sheet are. It must match your mattress height plus any topper. Standard pockets fit about 7 to 14 inches, deep pockets fit about 15 to 17 inches, and extra-deep pockets fit about 18 inches or more.
Our sleep team suggests measuring thickness at the edge from the bottom seam to the highest point of the top, including any topper, then adding 1 to 2 inches before you pick a pocket depth. A 17.25-inch pillow top, for example, needs an extra-deep pocket sheet to stay put.
California King and Split King Bedding
California king sheets are a different shape, so you need bedding made for 72 by 84 inches. Split kings usually use two twin XL fitted sheets with a single king flat sheet and comforter. For adjustable bases, split-top sheets are another option.
Moving and Delivering a King Mattress Through Your Home
A little planning keeps delivery day smooth.
Measure the Path
Measure every doorway, hallway, stairwell and tight turn between the front door and the bedroom. Most king mattresses travel on their side, so the doorway height and the turn at the top of the stairs matter most.
Easier-to-Move Options
Split king mattresses come in two twin XL pieces, so each one is easier to carry. Some foam models are lighter and more flexible than heavy hybrids. Luxury hybrid kings can weigh more than 200 pounds, which is a good reason to rely on professional delivery.
Haul-Away and Setup
Many local retailers, including Spencer's TV & Appliance, offer delivery, setup and haul-away of your old mattress. That saves you from wrestling an old king into a truck.
Pre-Delivery Checklist
- Measure doorways, halls and stairwells along the path.
- Clear furniture, rugs and decor from the route.
- Have the new frame or base ready for setup.
- Confirm haul-away for the old mattress.
Who Should Buy a King Size Mattress?
Ideal Buyers
- Couples who want more personal space.
- Parents who co-sleep with young kids.
- Pet owners who share the bed.
- Restless sleepers who move a lot at night.
When Another Size Fits Better
A queen may be the smarter pick for a small room, a tight budget or a solo sleeper. A California king makes more sense for sleepers over 6 feet or a long, narrow room. If you plan to use an adjustable base and want separate controls, look at a split king.
Quick Self-Check
- Is your bedroom at least 12 by 12 feet?
- Will you have 24 inches of walkway around the bed?
- Does anyone in the bed stand over 6 feet tall?
- Do you plan to add an adjustable base?
- Can your stairs and doorways handle a king?
Sleeping Cool on a King in the Arizona Heat
Bed size is only part of a good night in the Phoenix area. Summer nights stay warm, and a bigger bed can hold more heat if it is set up poorly.
- Pick cooling materials: Look for breathable covers, gel memory foam and pocketed coils that let air move through the mattress.
- Watch window placement: Keep the headboard away from west-facing windows that soak up afternoon sun.
- Choose breathable bedding: Cotton, linen and moisture-wicking sheets release heat better than heavy synthetic fabrics.
- Give memory foam time: Memory foam can feel firmer when cool and softer when warm, so let a new mattress adjust to room temperature for several hours.
Read More: The Coolest Mattress Tech to Keep You Cool This Summer | 10 Tips to Sleep Cooler Tonight
Top King Size Mattresses to Shop Now
These four Beautyrest king mattresses cover firm, medium and plush comfort, all in the standard king footprint. Each one is adjustable base compatible and assembled in the USA. Visit Spencer's TV & Appliance to lie down on each one and feel the difference.
Beautyrest Black® Series 3 Hybrid 14.5" Firm Smooth Top King Mattress
This firm hybrid king is made for sleepers who want strong support with deep, responsive pressure relief. Triple-Stranded Pocketed Coil Technology gives each partner individualized support and motion separation, so one person's movement stays on their side.
The patented ContourFit design cradles the body in FORM high density material, while Self-Response latex adds airflow and bounce. A Sleep Climate surface with Micro Diamond memory foam helps move heat away from the body, which is great for warm Phoenix nights. It is assembled in the USA and backed by a 10-year limited warranty.
Top Features
- Triple-Stranded Pocketed Coils: Individualized support with motion separation for couples.
- ContourFit Design: Hybrid construction that cradles the body for lasting pressure relief.
- Self-Response Latex: Maximizes airflow while contouring to your body.
- Micro Diamond Memory Foam: Helps move heat away for cooler sleep.
- Adjustable Base Compatible: Works with adjustable bases for custom positions.
Beautyrest Black® Series Four XCS 15" Hybrid Medium Tight Top King Mattress
This medium hybrid king hits the sweet spot between support and softness, making it a smart pick for couples with different sleep styles. Triple-Stranded Pocketed Coil Technology and 2K Micro Coils deliver individualized support with low motion transfer.
BlackICE Max Cooling Technology and a cool-to-the-touch Sleep Climate cover help you stay comfortable on hot nights. TotalEmbrace XHD memory foam and FORM HD Max material add pressure relief, while edge support makes the full 76-inch width usable from side to side. It is made in the USA and works with adjustable bases.
Top Features
- BlackICE Max Cooling: Advanced cooling technology for warm sleepers.
- 2K Micro Coils: Extra layer of coils for a responsive, contouring feel.
- TotalEmbrace XHD Memory Foam: Deep pressure relief for shoulders and hips.
- Edge Support: Lets you use the full surface without rolling off.
- Low Motion Transfer: Helps partners sleep without disturbing each other.
Beautyrest® World Class™ Level Three 16" Pocketed Coil Plush Pillow Top King Mattress
This plush pillow top king gives you a classic quilted feel with modern cooling and support. Its 1000-density Pocketed Coil Technology, with 1,088 coils in the king, works with higher density foams to provide individualized support and motion separation.
InfiniCool MAX Technology uses vertical natural fibers for advanced cooling. World Class Relief HD Foam and SurfaceTouch Gel Memory Foam offer responsive pressure relief right at the surface. The foams are CertiPUR-US certified, and the mattress is assembled in the USA and backed by a 10-year limited warranty.
Top Features
- Pocketed Coil Technology: 1,088 coils for individualized support and motion separation.
- InfiniCool MAX Cooling: Vertical natural fibers boost breathability.
- World Class Relief HD Foam: Responsive pressure relief that adapts to your body.
- SurfaceTouch Gel Memory Foam: Quilted into the top for instant comfort.
- CertiPUR-US Certified Foams: Tested foams for peace of mind.
Beautyrest Black® Series 4 Pocketed Coil® 17.25" Plush Summit Pillow Top King Mattress
This plush Summit Pillow Top is the most exclusive model in the Beautyrest Black collection. Two layers of 2K Nano Coils, for a total of 4K Nano Coils, work with Triple-Stranded Pocketed Coil Technology for highly conforming, individualized support.
Micro Diamond memory foam helps move heat away from the body, and ventilated Self-Response latex adds airflow. At 17.25 inches tall, it needs extra-deep pocket sheets. Eleven handles make it easier for delivery crews to move and position this luxurious king, and it is backed by a 10-year limited warranty.
Top Features
- 4K Nano Coils: Two layers of 2K Nano Coils for premium, conforming support.
- Triple-Stranded Pocketed Coils: Individualized support with excellent motion separation.
- Micro Diamond Memory Foam: Diamond-infused foam helps keep you cool.
- Ventilated Self-Response Latex: Airflow and responsive pressure relief.
- Eleven Handles: Makes moving and rotating this heavy king easier.
Making Sense of King Size Mattress Dimensions
King size mattress dimensions start with a 76 by 80 inch footprint that gives each sleeper 38 inches of space. Compare the standard king with the California king and split king, then measure your room and the full frame footprint before you buy.
When you are ready to choose, visit Spencer's TV & Appliance at one of our showrooms across the Phoenix area. You can test each mattress in person, get expert guidance from our sleep team and schedule local delivery and setup. You get personal service from a Valley retailer, not a big-box checkout line.
Frequently Asked Questions About King Size Mattress Dimensions
A standard king size mattress is 76 inches wide by 80 inches long, or about 193 by 203 centimeters. Height varies by model, from about 8 inches to more than 17 inches for luxury pillow tops.
A California king is not bigger than a king overall, since it has about 6,048 square inches compared with 6,080 for a standard king. It is 4 inches longer and 4 inches narrower, which suits taller sleepers.
A king size bed needs a room of at least 12 by 12 feet, though 13 by 13 feet or larger feels more comfortable. That extra space leaves room for walkways, nightstands and a dresser.
A king mattress is 16 inches wider than a queen, while both are 80 inches long. That gives each sleeper 38 inches of width on a king compared with 30 inches on a queen.
Split king mattresses usually use two twin XL fitted sheets instead of one king fitted sheet. You can still use a king flat sheet and comforter, or choose split-top sheets for adjustable bases.
Most king mattresses fit up stairs and through standard doorways when carried on their side. Measure tight turns and low ceilings ahead of time, since heavy hybrids can be hard to maneuver.
Why Trust Spencer’s TV & Appliance?
Since 1973, Spencer’s TV & Appliance has grown to 10 locations throughout the Phoenix Metropolitan Area. The secret to our longevity is simple: personal service. Customer satisfaction has always been the focus of our business, and throughout the years, we have been able to work hard with our suppliers to bring you the best prices. After all, getting customers the best price and personal attention is how we compete with big-box stores, day in and day out.
Not only do we offer top-rated appliances, name-brand electronics, and the best mattresses on the market but we also provide water treatment solutions and perform kitchen design services. Stop by your nearest Spencer’s and see what you’re missing!
Shop at Spencer’s Appliances in Phoenix
At Spencer’s TV & Appliance Stores Phoenix, we provide high-quality, name-brand products at great prices — check out our entire catalog to shop refrigerators, dishwashers, wall ovens, and so much more today. Your friends in the business are always happy to help you find the best kitchen appliances, mattresses, laundry appliances, and electronics for your humble abode, no matter what! Call us, or better yet, search for Spencer's appliances near me and stop by at one of our locations in the Phoenix, Scottsdale, and Glendale regions. Visit us today!
Learn More: Tips for Designing a High-End Kitchen