Why are we even asking this question? You're welcome, future self.
When you order a BFA bed, you can easily customize the overall height from the floor to the top of your mattress (we call this the seat height) by filling us in on the thickness of your mattress and boxspring/foundation, if applicable. Usually, measuring is straightforward, but if you use a pillowtop or adjustable mattress it can get tricky.
The goal of creating the ideal seat height isn't just for the most comfortable transition into and out of bed at night and in the morning - it's also so the headboard extends 2" or more past the top of your mattress so you don't incur the pillow problem (see attached, and don't end up buying a cheap piece of foam because you "lost you pillow").
Measure the thickness of your mattress at the edge, and you'll be all set. If you have an adjustable base and/or mattress, we'll build the frame ever-so-slightly larger and without a substructure so your mattress will fit perfectly inside the frame at any position. Let us know what the existing seat height looks like so we can create a headboard that's just right.
Questions? Let's connect.