That depends! In general, there are three main things to think about when it comes time to choose a size for your mattress: how many people will be sleeping on the mattress, the size of those people, and the dimensions of the bedroom.Bigger mattress sizes like Queens, Kings and California Kings are better when there are more people and/or a bigger space, while smaller sizes like Twin and Full /Double are better for single sleepers and/or smaller spaces. Click here to learn more. We carry a range of sizes from Twin all the way to Split California King. Here are the dimensions:Twin- 38” x 75” or 96.5cm x 190.5cmTwin XL- 38” x 80” or 96.5cm x 203cmFull-  53” x 75” or 134.5 x 190.5cmQueen- 60” x 80” or 152.5 x 203cmKing- 76” x 80” or 193 x 203cmCalifornia King- 72” x 84” or 183 x 213cm