While the weight of a king-sized bed varies depending on the manufacturer, quality, and kind of mattress, Hyatt estimates that a king-sized mattress weighs 95 pounds and a two-piece box spring set weighs 66 pounds. The mattress and foundation together weigh 161 pounds.
According to Amerisleep, innerspring mattresses are often lighter in weight than memory foam or latex foam mattresses. A memory foam mattress with a low density is a few pounds heavier than an innerspring mattress.
A memory foam mattress with a density of more than 4 pounds is over 30% heavier than an innerspring mattress. The weight of an innerspring mattress increases when a foam pillow-top is added.