The ones I got for the pups are 26" high; each of the 5 steps is 5.5" deep with a 4.5" rise. They are 12" wide. I put the stairs so they are parallel to the bed (i.e., on the 12" side) so they don't take much room, at the foot of the bed.
The steps are perfect for the Yorks ... it fits their stride to a "T". They come tearing into the bedroom, charge up the stairs, take a short hop to the top of the mattress and sit their like the King and Queen they know are
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The stairs are higher than the foot of the bed, but still a bit short of the mattress top, but it's not a problem.