The weight of a king-sized bed depends on the manufacturer, the quality of the mattress, and the type of mattress. According to Hyatt, a king-sized mattress weighs 95 pounds and a two-piece box spring set weighs 66 pounds. The weight of the mattress and base together is 161 pounds.
Amerisleep says that innerspring mattresses tend to be lighter than memory foam or latex foam mattresses. A memory foam mattress with a low density weighs a few pounds more than an innerspring mattress. An innerspring mattress weighs about 30 percent less than a memory foam mattress with a density of more than 4 pounds. When you add a foam pillow-top to an innerspring mattress, the bed gets heavier.