<p>If it helps, the posts on the corners of the bed are 2.25" square, I needed that dimension for some hangers I made to slide over the posts.</p>
<p>So, if you subtract the widths of the posts, you get the free clearance available for drawers below?</p>
<p>80 - (2.25 + 2.25")= 75.5"</p>
<p>And width-wise:</p>
<p>36 - (2.25 + 2.25") = 31.5. </p>
<p>Right?</p>
<p>Not quite, my recollection is that the length between the posts (inside to inside) is more like 81.5" but I will confirm that. The mattress itself is 80" long (twin xl), so I think there is a bit more between the posts. I think you are spot on with the width available between the posts though. However, I think some buildings use standard twin beds (75") so your mileage may vary.</p>