How Wide Is a King-Size Bed? (With Picture)

How wide is a king-size bed? A standard king mattress is 76 inches wide and 80 inches long, the widest standard size sold in the USA. This guide shares the king bed width in different units and compares it with other mattress sizes. You will also see how it fits frames, rooms and bedding.

Quick Conversion Section

Did you know? A standard king is the widest common mattress at 76 × 80 inches, while a California king is narrower but longer at 72 × 84 inches.

Quick Reference List

Standard and Regional King Widths

Not every king is the same width, so here is how each version measures up.

Standard King (Eastern King) Width

The standard king mattress, like the Casper Original Mattress in king size, is 76 inches wide and 80 inches long. That gives you a sleep surface of 6,080 square inches.

So when people ask how wide is a king-size bed, the answer for a Casper Original king is 76 inches. In feet, that is 6 feet 4 inches.

California King Width

A California king mattress, such as the Tempur-Pedic TEMPUR-Adapt in California king, is 72 inches wide and 84 inches long. That makes it 4 inches narrower than a standard king.

The Tempur-Pedic TEMPUR-Adapt California king suits tall sleepers who want extra legroom. It trades 4 inches of king mattress width for 4 inches of length.

Split King Width

A Split King, such as the Saatva Classic Split King, uses two Twin XL halves that are 38 inches wide each. Together they match the standard king width of 76 inches.

The Saatva Classic Split King pairs well with adjustable bases that move each half on its own. Each sleeper controls one 38-inch side.

Wyoming King Width

A Wyoming king mattress measures 84 inches wide by 84 inches long. That is 8 inches wider than the standard king bed width.

A Wyoming king mattress is rarely stocked in stores, so check frame and sheet availability first. It also needs a bigger room than a standard king.

Alaskan King Width

An Alaskan king mattress measures 108 inches by 108 inches, a full 9 feet on each side. That is 32 inches wider than the standard king-size mattress width.

An Alaskan king mattress needs a room of about 16 by 16 feet. It also usually calls for a custom frame and custom bedding.

King Bed Width vs Other Mattress Sizes

Comparing sizes is the quickest way to see how wide a king mattress really is.

King vs Queen Width

A Sealy Posturepedic queen mattress is 60 inches wide, while a standard king is 76 inches wide. That makes the king 16 inches wider.

Both the Sealy Posturepedic queen mattress and the king are 80 inches long. Only the king bed width changes.

King vs Full Width

A full-size mattress is 54 inches wide, so the standard king width adds 22 inches. The full-size mattress is also 75 inches long, 5 inches shorter than a king.

Two adults on a full-size mattress get about 27 inches each. On a king mattress, each adult gets about 38 inches.

King vs Twin and Twin XL Width

A Twin XL like the Purple Original Mattress is 38 inches wide and 80 inches long. Two of them side by side equal the king-size bed width of 76 inches.

Because the Purple Original Twin XL matches the king’s 80-inch length, two of them make a Split King. A regular twin is only 75 inches long.

King vs California King Width

A California king mattress is 4 inches narrower and 4 inches longer than a standard king. It measures 72 by 84 inches, while the king is 76 by 80.

Pick a standard king mattress when width matters most. Choose a California king mattress when length matters more than king bed width.

FAQ

How wide is a king-size bed in feet?

A standard king-size bed is 6 ft 4 in wide (76 inches). It is 6 ft 8 in long.

How wide is a king-size bed in cm?

A standard king is 193 cm wide and 203 cm long. That equals 1.93 m by 2.03 m.

Is a king bed wider than a California king?

Yes, a king is 4 inches wider (76 vs 72 inches). A California king is 4 inches longer.

How wide is a king bed frame?

Most king bed frames are about 78 to 81 inches wide. Check the exact product dimensions before you buy.

What room size do I need for a king bed?

A room of 12 by 12 feet gives comfortable walkways and nightstand space. Smaller rooms can work with a tighter layout.

Can two Twin XL mattresses make a king?

Yes, two Twin XL mattresses side by side measure 76 by 80 inches. That is the same size as a standard king.

Is a king bed wide enough for two adults?

Yes, each adult gets about 38 inches, the same width as a twin bed. That is plenty of room to sleep comfortably.

Conclusion

A standard king mattress is 76 inches wide, which is about 6 feet 4 inches or 193 cm. Always measure the frame, the room and your bedding along with the mattress. Use this guide to check the king bed width before you buy. For the inch, foot and centimetre units used here, see NIST’s SI units for length.

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Michael Carter

Hi, I’m Michael Carter, I write simple, everyday size guides so you can picture any measurement in seconds.