It's just as big as any king sized mattress you'd find in a store, I should have video'd it when I broke the Vacuum seal. It went from a box the size of an artificial Christmas tree box to a full size king sized mattress in under a minute. Also, unlike our last Sterns & Foster mattress with the springs in it, every move my gf made, I could feel it. Now...she could practically jump on her side of the bed and I wouldn't feel anything. Also, all my life I've never been able to sleep flat on my back, only on my sides or my stomach, now, for the last week I've slept every night on my back. I keep a lot on my mind and usually have trouble winding down and getting to sleep at night, now, as soon as my head hits that pillow, and my back hits that mattress, I'm zonked out and dreaming within 5 minutes. I feel so energized after just 4-5 hours of sleep on it. I am needing less sleep, and am way more productive, and clearheaded. I'm finally getting the REM recharge that I need. If you don't have one by the end of the year, I will gift you one. It'll change your life.