A king size bed measures 76 inches wide by 80 inches long, roughly 6 feet 4 inches by 6 feet 8 inches. That single fact answers the most common search query, but it does not tell you if a king fits your bedroom, how it compares to a queen, or why some “king” listings show different numbers. This guide covers the king bed dimensions, the room size you actually need, and the size mix-ups shoppers run into most.
Furniture retailers and mattress makers do not always agree on frame size versus mattress size. That gap causes real confusion at checkout. Here is the full breakdown, in plain numbers.
King Size Bed Dimensions (Standard Size Explained)
The standard king bed is 76″ wide x 80″ long (193 cm x 203 cm). This is sometimes called the Eastern king to distinguish it from the California king. It is the widest mattress sold in standard US sizing, giving each sleeper roughly the same width as a twin bed.
King Bed Dimensions in Inches, Feet & Centimeters
In feet, a king size bed is about 6 feet 4 inches wide by 6 feet 8 inches long. Here is the same measurement across units:
| Unit | Width | Length |
|---|---|---|
| Inches | 76″ | 80″ |
| Feet | 6’4″ | 6’8″ |
| Centimeters | 193 cm | 203 cm |
Mattress depth (thickness) typically runs 9 to 16 inches, depending on the number of foam and coil layers. Thicker mattresses, especially hybrid and pillow-top models, sit at the higher end of that range.
How Big Is a King Size Bed Frame vs. Mattress?
The mattress and the bed frame are not the same size. A frame adds anywhere from 2 to 6 extra inches on each side to hold the mattress in place, plus more at the head for a headboard. A simple platform frame might total 78 to 82 inches wide, while a frame with a thick upholstered headboard can push past 82 inches. Always check the frame’s outer dimensions, not just the mattress size, before measuring your room.
Our interactive Size Visualizer Tool helps you accurately visualize dimensions, making it easier to understand the true size of everyday objects and spaces.
King Bed Size vs. Other Standard Bed Sizes
Comparing a king bed size to other mattresses is the fastest way to picture how much floor space you are adding. Here is how the major sizes stack up.
| Bed Size | Width | Length | Best For |
|---|---|---|---|
| Twin | 38″ | 75″ | Kids, single sleepers, small rooms |
| Full | 54″ | 75″ | Solo sleepers who want extra room |
| Queen | 60″ | 80″ | Couples in average-size bedrooms |
| King | 76″ | 80″ | Couples, co-sleeping families, larger rooms |
| California King | 72″ | 84″ | Taller sleepers needing extra legroom |
King vs. California King Dimensions
A California king measures 72″ wide by 84″ long, four inches narrower and four inches longer than a standard king. The tradeoff is simple: standard king gives more shoulder room, California king gives more legroom. Taller sleepers over 6 feet often prefer the California king for that extra length. Note that California king bedding does not fit a standard king, and vice versa, so check the label before buying sheets.
King vs. Queen Size Bed Dimensions
A king bed is 16 inches wider than a queen (76″ vs. 60″) but shares the same 80-inch length. That extra 16 inches matters more than it sounds. Split between two sleepers, it is the difference between elbow-to-elbow contact and genuine personal space. Queen remains the most-purchased mattress size in the US, chosen by an estimated 41% of shoppers, compared to about 18% who buy king, according to shipment data from the International Sleep Products Association. King demand has been climbing steadily since 2010, when it accounted for just over 10% of shipments.
Must Visit: How Big Is 1500 Square Feet? 12 Real-Life Examples, Floor Plans and Layout Ideas
What Room Size Do You Need for a King Bed?
Interior designers and furniture retailers commonly recommend a minimum bedroom size of 12 feet by 12 feet to comfortably fit a king bed along with a dresser, nightstands, and walking space. Anything smaller works, but with tighter clearance around the bed.
Minimum Bedroom Size for a King Bed (Recommended Layout Space)
For comfortable movement, leave at least 24 inches of clearance on each side of the bed and at the foot, per general furniture-placement guidance used by interior designers. That clearance is what pushes the recommended room size up to 12×12 rather than the bare minimum needed to fit the mattress alone.
Visual Guide: King Bed Size in Feet (5×7 Comparison)
Picturing “76 inches by 80 inches” is hard. Picturing “just over 5 feet by just under 7 feet” is easier for most people, since it maps to a rectangle you can pace out on the floor.
King Bed Size at a Glance (Quick Comparison Chart)
- Standard king: 76″ x 80″ (6’4″ x 6’8″)
- California king: 72″ x 84″ (6′ x 7′)
- Split king: two 38″ x 80″ Twin XL mattresses combined to equal 76″ x 80″
- Alaskan king: 108″ x 108″ (9′ x 9′), the largest mattress size in regular production
- Recommended room: 12′ x 12′ minimum for comfortable clearance
Choose the Right King Bed for Your Space
Matching a king bed to your room comes down to three checks: floor space, doorway clearance, and bedding compatibility.
King Bed Headboard & Bedding Size Considerations
A king headboard typically measures 78 to 81 inches wide, matching the mattress width, and stands 48 to 65 inches tall depending on style. King sheets, comforters, and duvets are cut specifically for the 76×80 mattress and will not stretch to fit a California king, since that mattress is narrower but longer. Buying the wrong bedding size is one of the most common (and avoidable) mistakes after a king bed purchase.
Signs Your Room Is Too Small (or Perfect) for a King Bed
A room works well for a king bed if you can open closet and entry doors fully without hitting the frame, and if at least one side of the bed keeps 24+ inches of walking space. Warning signs include a bedroom under 100 square feet, a single small window that limits furniture placement, or a layout where the only outlet access sits behind where the headboard would go.
FAQs
What size bed is 5 feet by 7 feet?
No standard US mattress is exactly 5 feet by 7 feet. The closest match is a queen bed, which measures 5 feet by 6 feet 8 inches (60″ x 80″).
What is the standard size of a king bed?
The standard king size bed measures 76 inches wide by 80 inches long (193 cm x 203 cm), also called an Eastern king.
How big is a king bed in feet?
A king size bed is about 6 feet 4 inches wide by 6 feet 8 inches long.
Can a king bed fit in a 12×10 room?
Yes, a king size bed fits in a 12×10 room, though clearance around the bed will be tight with limited space for extra furniture.
Is a 5 by 6 bed king or queen?
A bed close to 5 feet by 6 feet 8 inches is a queen. A standard king is wider, at 6 feet 4 inches by 6 feet 8 inches.
Conclusion
A king size bed measures 76″ x 80″, the widest standard mattress made in the US, and works best in bedrooms of 12×12 feet or larger. Whether you are comparing king vs. queen or checking if your room can handle the extra width, the numbers above give you the exact measurements to plan around before you buy.
Measurement Researcher, Size Comparison Writer & Content Specialist
Timmy Ahad is a dedicated content writer and research specialist at SizesVisualizer.com, where he focuses on creating accurate, easy-to-understand content about measurements, dimensions, size comparisons, and real-world object visualization.
