Side-by-side comparison
Same scale. See the difference at a glance.
King
76 × 80 inches
4 inches wider
More space for sharing.
California King
72 × 84 inches
4 inches longer
More room to stretch out.
| Feature | King | California King |
|---|---|---|
| Width × Length | 76 × 80 | 72 × 84 |
| Width per sleeper | 38″ | 36″ |
| Surface area (sq in) | 6,080 | 6,048 |
Mattress dimensions only, measured separately from the bed frame. Check the exact mattress and frame measurements before ordering.
Start with your priorities
Shop KingMore width?Width for sharing
King is 4 inches wider — a bit more personal space for two.
Shop California KingMore length?Length for stretching
California King is 4 inches longer: more room at the foot if you stretch out.
Existing frame and bedding
Consider your current bed frame, sheets and comforter sizes when switching.
Will it fit your room?
Here’s how each size fits in a 12 × 12 ft bedroom (illustrative).
King with frame (80″ × 86″)
Assumed frame: 80 × 86 in (mattress + frame)
Space around the bed
32 inches on each side
58 inches at the foot
California King with frame (76″ × 90″)
Assumed frame: 76 × 90 in (mattress + frame)
Space around the bed
34 inches on each side
54 inches at the foot
Illustrative frames in an otherwise empty 12 × 12 ft room, centered with the head against the wall. These are not measurements of a frame we sell, or accessibility guidance. Furniture and doors reduce clearance: measure your frame and delivery route.
Open room planner
Choose the feel. Then choose the size.
Compare the same model and feel in each size. Current prices and availability are on the product page.
Complete your setup.
Find the right support and essentials for a better night’s sleep.
Bedding & base compatibility
Buy fitted sheets and a protector labeled for the exact mattress size, with a pocket depth that accommodates its height. King fitted bedding is shaped for a wider, shorter mattress; California King fitted bedding is shaped for a narrower, longer one. A comforter or duvet may have different sizing rules, so compare its actual measurements and the drop you want.
For a concrete example, Helix lists separate King and California King protector dimensions. Check the product you are buying rather than assuming every brand uses the same pocket depth. Browse protectors and sheets by the required size.
A frame must support the mattress’s footprint and meet the mattress manufacturer’s support instructions. Some adjustable frames accept multiple sizes, but only use a configuration the frame manufacturer specifies. Confirm center support, slat spacing and the exact foundation or base size before reusing an existing setup.
Compare the complete cost.
Factor in everything, from support to delivery.
- Mattress
- Matching support
- Bedding
- Delivery & applicable fees
Why California King?
U.S. News describes competing origin stories: a luxury bed for Hollywood actors in the 1930s–1940s, or a postwar design for large Los Angeles homes. These are theories, not a settled origin story. California King’s possible origins (opens in a new tab) · U.S. News
King vs California King questions, answered.
Is California King bigger than King?
It is longer, but narrower. King has slightly more surface area. Use the dimension table to compare the direction in which you need more space.
Will a California King fit a King bed frame?
Do not assume it will. The mattress footprints differ. Check the frame’s approved configurations and mattress support requirements; our foundation collection is a starting point for finding the matching size.
Can I use King sheets on a California King?
Choose fitted sheets and a protector in the matching size. For flat sheets and duvets, check actual measurements and desired overhang. Compare the available sizes in our sheet collection.
Do two Twin XL mattresses make a California King?
No. Two 38 × 80-inch Twin XL mattresses side by side make a 76 × 80-inch Split King. A Split California King uses two 36 × 84-inch halves. See the manufacturer’s split-size explanation and our size chart.
Which size is best for a tall sleeper?
Try the extra length in your normal sleeping position, with a pillow and any footboard taken into account. There is no exact height cutoff that works for everyone. Use the showroom directory to arrange a comparison of displayed options.
Bring your measurements.
Check your room size, doorways and stairs before you buy.