Twin mattresses are 39 inches wide and 75 inches long. A sample of twin mattresses listed for sale online included a range from 50 to 95 pounds and an average weight of 71.8 pounds.
Queen-sized mattresses are 60 inches wide and 80 inches long. A sample of queen mattresses listed for sale online included a range from 60 to 93 pounds and an average weight of 81.4 pounds.
King-sized mattresses are 76 inches wide and 80 inches long. A sample of king mattresses listed for sale online ranged from 63 to 112 pounds and had an average weight of 92.2 pounds.
Over time, the weight of mattresses increases due to the accumulation of dead skin cells, dust mite debris, sweat and other factors. Estimates suggest the weight of a mattress may double over the course of 10 years.