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 Will my sheets fit on a Casper Mattress? Once I take my mattress out of the box, how long does it take to expand? 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?