1 8 Spacer Subway Tile . Smaller tiles, up to 8 x 8. See also tile city and stone camarillo. Tiling my kitchen backsplash with white subway tiles. I'm using using 1 from www.pinterest.com Tile spacers come typically in the following sizes: This is especially the case for walls. The most popular grout line sizing for 3” x 6” subway tiles is 1/16” and 1/8”.