Just the size! A California King (72 x 84 inches) is four inches narrower (side to side) and four inches longer (head to toe) than a King (76 x 80 inches).

The difference simply comes down to the shape (no knowledge of geography required). Many sleepers love the extra width that the King provides, especially those with children and/or pets who like to pile into bed on those long, lazy weekend mornings. The California King, in addition to providing prime real estate for your dog who loves the foot of the bed, is a popular choice among taller sleepers. In other words, a King is the widest and the California King is the longest conventionally-sized mattress.

If visualizing the different sizes is making your head spin, we recommend taking a roll of masking tape and blocking out the two sizes on the floor of your bedroom, allowing an inch or two on each side for your bed frame. The four inches of length versus four inches of width can make a big difference for sleepers and for the orientation of a bedroom. Ultimately, it’s all about how you like to stretch out! Weighing the differences between a King size and California King size mattress shouldn’t cost anybody any zzz’s, so feel free to grill our sleep experts at (888) 498-0003, and they can help you through it.

When buying a mattress to use with an existing bed frame, we strongly recommend double-checking the size of your current mattress (trust us on this one). A minute or two with your tape measure may reveal that the King mattress you’ve been dying to replace for ten years is actually the California King mattress you’ve been dying to replace! A few measurements ahead of time will help make sure that you don’t end up trying to fit a California King mattress into a King-sized bed frame (even though if it happens, we’re happy to help you get it sorted). Same goes for a double-check on sheets.

Your fitted sheets will be specific to a King or Cal King mattress; however, most providers offer a flat (or top) sheet and duvet to use with either type of king. So you won’t always need to order a whole new set when changing mattress sizes.

But where did this whole California King vs. King thing start, anyway? The history of the term California King is a bit murky, but everybody seems to agree that it did originate in the Golden State. Our research indicates that a Los Angeles-based furniture company began making these extra-long mattresses for Hollywood celebrities who wanted an even bigger mattress to fill out their master bedrooms (talk about a good problem to have). The one thing that doesn’t add up, in our minds, is why they hacked off those four inches on the side!? Maybe it’ll all make sense when we’re famous movie stars...