FAQ MATTRESSES HOW TALL IS THE ORIGINAL MATTRESS? SEE ALL QUESTIONS HOW TALL IS THE ORIGINAL MATTRESS? The Original mattress is 11 inches tall. YOU MAY ALSO LIKE Once I take my mattress out of the box, how long does it take to expand? Will my sheets fit on a Casper Mattress? Can I use an adjustable bed frame? What are the dimensions of the Original mattress? What’s the difference between a bunkie board and a box spring?