While the weight of a king-sized bed varies by manufacturer, quality and mattress type, Hyatt estimates the weight of a king-sized mattress as 95 pounds and the weight of the two-piece box spring set at 66 pounds. The overall weight of mattress and foundation is 161 pounds.
Innerspring mattresses are generally lighter in weight than memory foam or latex foam mattresses, according to Amerisleep. A low-density memory foam mattress is a few pounds heavier that an innerspring mattress. A memory foam mattress with a density of greater than 4 pounds weighs almost 30 percent more than an innerspring. Adding a foam pillow-top to an innerspring mattress increases the weight of the bed.