Did you know that there are more mattress sizes in the United States than in any other part of the world? If you are shopping for a mattress for the first time, it may be difficult to work out what size you should go for. Factors to consider when selecting a mattress are whether the bed is for one person or two people, and what size of room it is going into.

A twin mattress measures 39 by 75 inches and is ideal for a teenager or a single adult. If you (or your teen) are particularly tall, go for a twin XL, which is the same width but 80 inches long. A twin mattress is usually the first mattress a child will sleep on when she becomes too big for a cot mattress (30 by 70 inches). If your toddler or child looks too big for their mattress, it is time to invest in a new one. Think about your future needs at this point. If you often have overnight guests, consider buying a full size mattress for your child that guests can sleep on when they visit. A larger mattress will also give your child years of use as he or she grows.

The next size up from a twin XL is a double or full mattress. This measures 53 by 74 inches and is one of the most popular mattress sizes, because it is big enough for two people but will fit comfortably into the majority of bedrooms. The double/full is also available in XL, which is 80 inches long.

If you are looking for a larger sleeping surface, you have the options of a queen mattress (60 by 80 inches), a king mattress (76 by 80 inches) and a California king mattress (72 by 84 inches). Some manufacturers offer an even larger mattress, which is generally made to order as there is far less demand.

Use these dimensions to work out the best mattress for you. If you already have a bed frame or box spring, you will need to choose the mattress that fits. When you have a rough idea of the best size, try out several mattresses in the show room to determine which one best meets your needs. Size is important, but you must not forget about comfort and support!