Twin size not cutting it? If you have additional space in your bedroom but not enough for a queen-size mattress, a full-size can be just the solution. Measuring 75” x 54”, full-size mattresses will give an individual or couple a significant amount of sleep space compared to a twin-size mattress. Sixteen inches wider, a full-size mattress is perfect for those who need more sleep space but are confined to a small bedroom space. Sleep Outfitters carries 32 full-size mattresses from Sealy, Tempur-Pedic, and Stearns & Foster, starting as low as $184.