If you’re shopping for a new bed, you probably want to know what is the size of a king mattress. It’s one of the most popular choices for master bedrooms, offering ample space for couples or anyone who loves to spread out. This guide will give you all the details you need, from exact dimensions to shopping tips, to ensure you make the perfect choice for your sleep needs and your room.
What Is The Size Of A King Mattress
A standard king-size mattress, often called an Eastern King, measures 76 inches wide by 80 inches long. That’s 6 feet 4 inches wide and 6 feet 8 inches long. This provides each person in a couple with 38 inches of personal sleeping space, which is equivalent to the width of a twin mattress. It’s a significant upgrade from a queen, adding 16 inches of width for much more elbow room.
Standard King vs. California King: The Key Difference
It’s crucial not to confuse the standard king with the California King. While both are large, they have different shapes that suit different needs.
- Standard King (76″ x 80″): Wider and shorter. Best for couples who want maximum width to sleep without disturbing each other.
- California King (72″ x 84″): Narrower and longer. Ideal for taller individuals (over 6’4″) or for bedrooms that are longer than they are wide.
Always double-check which “king” a retailer is referring to, as the size difference will affect your sheets, bed frame, and room layout.
Breaking Down the Dimensions in Practical Terms
To visualize the size, think of it this way. A king mattress is the same width as two twin XL mattresses placed side-by-side. Its surface area is a generous 6,080 square inches. That’s plenty of room for you, your partner, pets, or kids who might wander in during the night. You’ll need a bedroom that’s at least 12 feet by 12 feet to comfortably fit a king bed and have walking space around it.
Who is a Standard King Mattress Best For?
- Couples who value personal sleep space.
- Families with young children or pets who share the bed.
- Individuals who move around a lot during sleep.
- Anyone with a spacious primary bedroom.
Required Room Size for a King Bed
You can’t just plop a king bed into any room. You need adequate space for movement and other furniture. A good rule of thumb is to have at least 2 feet of walking space on three sides of the bed. For a standard king (76″ x 80″), your room should ideally be:
- Minimum: 12 feet by 10 feet. This will fit the bed but feel snug.
- Recommended: 14 feet by 12 feet or larger. This allows for nightstands, a dresser, and easy movement.
Always measure your room carefully, including the placement of doors, windows, and closets, before committing to this size.
Choosing the Right Foundation and Frame
Your king mattress needs proper support. The wrong foundation can void warranties and lead to premature sagging.
Types of Supports for a King Mattress
- Box Spring: A traditional choice that raises the bed height. Ensure it’s a king-size box spring designed for a split king setup (two twin XL box springs) or a single, rigid model.
- Platform Bed: Features a solid or slatted base built into the frame. Eliminates the need for a box spring. Slats should be no more than 3 inches apart for proper support.
- Adjustable Base: Allows you to elevate your head or feet. These are fantastic for reading, watching TV, or alleviating snoring and acid reflux. Make sure you get a king-size model.
- Bunkie Board: A thin, solid platform that sits on a bed frame to provide a flat, supportive surface, often used with slatted frames that have gaps that are too wide.
Bed Frame Considerations
Your bed frame must be designed for a king’s weight and dimensions. Remember that a king mattress is heavy, often over 100 pounds. A sturdy frame with a center support leg (or several) is non-negotiable for preventing sag and ensuring stability. Metal frames tend to be very supportive, while wooden frames should be made from solid hardwood.
The Shopping Process: A Step-by-Step Guide
Buying a king mattress is a big decision. Follow these steps to make a smart purchase.
Step 1: Measure Your Space (Twice!)
Grab a tape measure and note the dimensions of your bedroom. Mark out the floor with painter’s tape to visualize the bed’s footprint. Don’t forget to account for other furniture and door swings.
Step 2: Set Your Budget
King mattresses range from a few hundred to several thousand dollars. Determine your comfortable spending range before you start looking. Remember to factor in the cost of a foundation, frame, and new bedding, which can be significant for a king size.
Step 3: Research Mattress Types
Each type offers a different feel. Here’s a quick breakdown:
- Innerspring: Traditional feel with bouncy support. Good for airflow.
- Memory Foam: Contours to the body, relieves pressure points. Can retain heat, though many now have cooling gels.
- Latex: Responsive and buoyant, often cooler than memory foam. Durable and hypoallergenic.
- Hybrid: Combines coils with foam or latex layers for a balance of support and comfort. Very popular right now.
It’s wise to test different types in person if you can, as your personal preference is key.
Step 4: Consider Sleep Partners
If you share the bed, consider your partner’s needs. Do they have different firmness preferences? Do they get up often? Motion isolation is crucial—memory foam and latex are excellent at preventing movement from transferring across the bed. For couples with different firmness needs, a split king with two adjustable bases might be the ideal, though more expensive, solution.
Step 5: Check Policies and Reviews
Always review the warranty (look for at least a 10-year limited warranty), trial period (many online brands offer 100+ nights), and return policy. Read customer reviews to learn about real-world durability and comfort over time.
King Size Bedding and Accessories
Your old queen sheets won’t fit. You’ll need to invest in a new set of king-size bedding.
Sheet Sizes and Thread Count
King-size fitted sheets are designed for a mattress up to about 76″ x 80″. Deep-pocket sheets are essential if your mattress is over 12 inches thick. For thread count, a range between 300 and 500 is often the sweet spot for softness and breathability; higher numbers aren’t always better.
Comforters, Duvets, and Bed Skirts
A standard king comforter is typically 106 inches wide by 92 inches long, designed to drape over the sides of the bed. A duvet cover should match these dimensions. A bed skirt or valance will need to be king size, often split-corner to fit around bed posts or a footboard.
The Blanket and Pillow Upgrade
You’ll likely need new blankets, and king-size pillows (often 20″ x 36″) are a great addition to fill the wide space. Standard pillows can look lost on such a large bed.
Common Challenges and Solutions
Owning a king bed comes with a few unique hurdles. Here’s how to solve them.
Challenge 1: Getting it Through the Door
A king mattress is bulky. Measure your hallways, staircases, and door frames before delivery. Many modern foam mattresses come compressed in a box, which solves this problem entirely. Traditional innerspring kings may need to be angled or, in rare cases, brought in through a window.
Challenge 2: Making the Bed
It’s a lot of real estate to cover. Make it easier by putting the top sheet and comforter on from side to side, not top to bottom. Walking around the bed is part of the process—embrace it.
Challenge 3: Finding Affordable Bedding
King bedding is more expensive. Shop sales, consider sets from warehouse clubs, and look for quality mid-range brands. Investing in two good sets can be more economical than buying several cheap ones that wear out quickly.
Challenge 4: Moving a King Mattress
It’s a two (or three) person job. Use mattress straps for carrying, and a mattress bag to protect it during transit. Professional movers are often worth the cost for such a large, heavy item.
FAQs About King Mattress Sizes
Is a king mattress the same as a queen?
No, a king mattress is significantly larger. A queen is 60″ x 80″, so a king adds a full 16 inches of width while maintaining the same length. That extra width makes a major difference for couples.
What’s bigger, a king or a California king?
They are different. A standard king is wider (76″ vs. 72″), while a California king is longer (84″ vs. 80″). In terms of total area, a standard king has slightly more square footage than a Cal king.
Can I use two twin box springs for a king?
Yes, a standard king mattress often uses two twin XL box springs (each 38″ x 80″) side-by-side. This setup is actually easier to maneuver up stairs and through doorways. Just make sure your bed frame is designed to support them properly.
Do I need a special bed frame for a king?
Yes, you need a frame specifically built for a king mattress’s dimensions and weight. It must have adequate center support to prevent the mattress from sagging in the middle, which is a common issue with poorly supported kings.
How much bigger is a king than a full?
A full mattress is only 54″ x 75″. A king is 22 inches wider and 5 inches longer. It’s nearly double the sleeping space of a full bed, making it a great upgrade for a single sleeper who wants luxury or a couple who is currently cramped.
Are all king mattresses 80 inches long?
Most standard kings are 80 inches long. However, some “oversized” or custom brands may vary slightly. Always check the product specifications before you buy, especially if your or your partner is very tall. The California king is the standard choice for extra length at 84 inches.
Final Checklist Before You Buy
Ready to purchase? Run through this last list:
- ✓ Measured bedroom and verified a king will fit comfortably.
- ✓ Chosen between Standard King and California King based on needs (width vs. length).
- ✓ Budget includes mattress, foundation/frame, and new bedding.
- ✓ Researched mattress types and tested if possible.
- ✓ Considered partner’s needs (motion isolation, firmness).
- ✓ Checked warranty, trial period, and delivery/pickup options.
- ✓ Measured your home’s entryways to ensure the mattress can be delivered.
Choosing a king mattress is an investment in your sleep and well-being. By understanding the true size, requirements, and commitments involved, you can confidently create a bedroom oasis that offers comfort and space for years to come. Take your time, do your research, and you’ll find the perfect large-format bed for your home.