French Bed. This appears to be a full size bed. The distance between rails is 54 ½ approx. A full bed is 55” wide. The footboard is 61 ½ at the widest. The headboard is 61 ¾ at the widest. It flares out at the top so the “waist” of the headboard is 57 ¾. We measured between the slots for the rails so the distance between the rails might be off a bit from how a mattress fits on top of them. We only used the headboard against the wall and used king size mattresses and a king size frame sitting in front of the headboard. The footboard and side rails stayed stashed away. You can add extenders to the bed if you want to use the footboards and side rails with a larger mattress than they were designed for. We can’t take any responsibility as to whether a standard full mattress will fit.