Once you've determined the overall size of your tile mural, take the width in feet times the height in feet to figure out the square footage. Round up to the nearest foot for both sides. A mural that is 4' feet wide by 3'7" high, is figured as 4 x 4 = 16 square feet. 16 x $80/square foot = $1,280. You would enter "16" as the quantity for the number of pieces. We will adjust the actual charge based on the final layout for your mural and contact you with the adjusted amount. Tiles are available in 4.25" x 4.25", 6" x 6", 6" x 8", 8" x 8" and 12" x 12". You need to select one tile size for the entire mural - if your design is complex, such as a building with many windows, a racetrack, an English garden or the like, we recommend the larger tiles - if your design is less complicated, choose any tile size. All tiles are available in a semi-gloss finish - it's stunning!