Do you or your partner roll around or sprawl out in bed? Do you wake up with pets or your children in bed with you? Are you a single sleeper who sleeps like a starfish or thrash around like swordfish? If you answered 'yes' to any of these questions, a king might be the best mattress size for you.

King size bed dimensions: 76 inches by 80 inches (193 centimeters by 203.5 centimeters). For room planning, a king size bed dimensions in feet are 4.42’ by 6.67’. 

This ample square footage provides each person in a couple with a twin XL worth of sleeping space - in fact, if you push two twin XL mattresses together, you'll be able to use king-size bedding with it (this is called a "split king"). It lends luxurious space to a single sleeper or provides enough space for a family to co-sleep.

Many couples go for the king over the queen because of the additional space: it provides more motion isolation, more space to sprawl, and - though this is less critical with cooling gel memory foam mattresses like the Yogabed - more thermal isolation.

The extra space provided by a larger mattress has a variety of health benefits as well. Not being cramped up against another person allows for improved blood flow, easier breathing, less pressure on tendons and joints, and better sleeping positions. 

King mattresses are great for master bedrooms: while many beds may be dwarfed by a larger room, a king bed will fill the space nicely, especially accompanied by a nice bed frame and headboard. However, a king bed can find a place in many other rooms: so long as the room is at least 10 feet by 12 feet (providing space for nightstands and a dresser), or 13 feet by 13 feet (providing space for more furniture), your king size bed should fit well.

There is a common space-related concern regarding king beds. Even if your bedroom is large enough, how will you get it up the stairs and through your hallways? Fortunately, buying a bed in a box solves this problem: the mattress is compacted for shipping, so when your mattress arrives, you can simply move the box into your bedroom, set it out, and then let it expand to its full size.

In terms of box springs or foundations, if you don't have room to bring a king foundation into your house: because two twin XL beds make up a king, you can use two Twin XL box springs or foundations to support your king mattress.

The difference between a standard king and a California king mattress is in width versus height.

A California king bed takes 4  inches off the width of the standard king and adds it to the height, changing the mattress dimensions in feet from 4.42’ by 6.67’ to 6’x 7’ (or from 76 inches by 80 inches to 72 inches by 84 inches). The Cal king is often the first choice for tall people, especially those over 6 feet because of its extra length but with a slightly smaller width. Make sure to measure your room before you get any new bed, but especially the large king and California king mattresses. You wouldn't want to buy a fancy new bed only to find it won't fit!