The King size mattress is the widest mattress on the domestic marketplace. Measuring 76” in width and 80” in length, a King size mattress is an excellent option for couples and growing families. Buying a King size mattress can often help couples with sleep issues like partner disturbance and motion transfer. By having more real estate devoted to the mattress in your bedroom, you can experience more personalized sleep. Buyer Beware: measure your sleeping space before investing in a King size mattress to assure that your bedroom can accommodate your beautiful new bed. Now that you know the size mattress you prefer, shop below by Brand, Comfort Level, or Type to find the perfect mattress for you.