Twin extra long: a twin extra long is a twin bed that's 5 inches longer than its traditional
counterpart, 39" x 80" instead of 39" x 75". This is perfect for someone who is tall, and these are used often for adults in places like college dorms. Before you buy an extra long twin bed, though, you should be aware that it may take a little hunting to find extra long twin sheets. These are not as readily available as regular twin sheets.

Double or full size: Double mattresses are 54" x 75". They're perfect for two average sized people who share a bed, or are also a good solution for someone who sleeps alone but likes a lot of extra room. When you think about mattress sizes, remember that the basic double or full size is the same length as a twin bed. This can be an advantage if no one sleeping on it is particularly tall and it needs to fit in a particularly small space such as a studio apartment or single bedroom apartment.

Queen size: Queen mattresses are 60" x 80". These can be quite roomy when compared to a double bed. They are 6 inches wider and 5 inches longer than a double bed. This can make for much better sleeping arrangements, especially for larger people. Depending on where you want the bed to go, though, keep in mind that this size of mattress is going to be a little bit harder to maneuver than smaller mattresses.

King size: A king-sized mattress is the same length as a regular queen bed and another 16 inches wide. This gives to people sleeping together quite a bit of extra room. This bed can sleep two large adults comfortably. However, as with the queen sized mattress only more so, this size mattress can be difficult to maneuver, especially down narrow hallways or stairs.

California king size: a California king size mattress is 72" x 84" and definitely takes up a lot of
space. It's perfect for taller people but once again, you're going to need to make sure it fits
where you're going. One quick way to measure is to lay three normal sized pillows end to end to determine its width