What Size Mattress Do I Have?
How to Measure a Mattress
Mattress size is determined by the length and width. To figure out the size of your own mattress, first place a measuring tape in a straight, flat line starting at the top seam and extending to the bottom. This dimension is the length. Next, measure the broadest portion of the mattress, from left to right, to establish width. These two numbers give you enough input to determine which of the six standard mattress sizes you own.
In addition, measure from the bottom of your mattress to the very top of the crown (highest point). This is the profile of your bed and will help you in purchasing a new mattress of a similar or different height, depending on how well you like the profile of your current mattress.
Common Mattress Sizes
Twin mattresses, some of the smallest on the market, measure 38 inches wide by 74 inches long. The slightly longer twin XL mattresses, most commonly found in dorms, are 38 inches wide by 80 inches long. Full beds are slightly larger, measuring 54 by 74 inches. The popular queen size mattress is about 60 inches wide and 80 inches long. Finally, king beds measure 76 inches wide by 80 inches long, while California king mattresses are 72 inches wide by 84 inches long. All size measurements are general, and individual mattress specifications can vary up to 1 inch.