A twin XL size mattress is 5 inches longer than a twin, making it perfect for growing children or adults with a small space. A twin XL is the standard mattress size for most colleges. Plus, two twin XL mattresses together make a king. This setup is ideal for a split adjustable base, so you and your partner can both customize your ideal sleeping position.

A queen-size mattress is the most popular mattress size, giving you an extra 6 inches of width over a full-size mattress. A queen is a great choice for single sleepers (and your furry friend!) and couples who may not have enough space for a king-size mattress.

A California king-size mattress isn't quite as wide as a king mattress, but is an extra 4 inches longer, making it ideal for taller sleepers. A California king will provide you and your partner with plenty of space and a little extra length.