You can't do a check pattern with a tile that large in spaces that small. There's no room for the pattern to establish itself.

In the foyer, you'll only have one full tile down the center of the 6'10" space alternating with just over 2 full tiles (and some nubbin fillers to make up the extra inch needed on each side--33.9" diagonal on the tiles).

Thank you! Would an 18x18 work?

Nope 18" x 18" is still 1.5ft x 1.5ft. The bathroom is only 6'8" wide and that's WALL TO WALL. The FLOOR space (where you can put your feet) is going to be around 3ft (36 inches). That means an 18" x 18" tile is going to have exactly 2 tiles of width. Yikes! Total design fail.

In a bathroom, you have to imagine JUST the foot space (before you stub your toe on the bathtub or the shower surround or the cabinets). You need to look to a size that is smaller than 12" x 12".

Even your Foyer is too small for an 18" x 18". A 12" x 12" is possible in the foyer...and if the tile installer is SUPER NEAT they can get this to set up in the bathroom. A tile this size in your small bathroom is going to look more like an argyle or a harlequin pattern. The checker board pattern will not show itself in such a small space.

The proportions are too off. I’d suggest not going with a checkerboard of any size. It’s a look that doesn’t take well to small spaces. Stick with a single flooring material

through the home, as much as possible.