Okay, this is going to feel super old school (actually, grade school), but hear us out!
The way to find your true fit from home is to trace each foot and simply measure length and width.
Grab a sheet of paper, a pencil, and a ruler.
Place the paper on a flat surface and trace around your foot with the pencil. The key is to keep the pencil at a straight 90 degree angle and make sure the pencil is touching your foot the entire time. Do this for both feet.
Place your paper on a flat surface and measure the length from the top of your second toe to the bottom of your heel. Next, measure the widest point of your foot. Do this for both feet.