Tile Grout Calculator

How it is calculated

Tile length, tile width, joint width and joint depth are all entered in inches, and the covered area in square feet. First the tool finds the grout per square foot: lb per sq ft = ((L + W) ÷ (L × W)) × joint × depth × 9.5, where L and W are the tile sides. The fraction (L + W) ÷ (L × W) is proportional to the total length of joint lines per unit of area, so smaller tiles give a larger value. The total is grout = lb per sq ft × area, shown in pounds to one decimal. All five inputs must be greater than zero. Fractions of an inch must be typed as decimals, for example 0.125 for 1/8 inch. The result is a net estimate with no allowance for waste, uneven tile edges or grout left in the bucket, and different grout types vary in density.

Common mistakes

• Typing the joint as 1/8 or 3 mm. The field wants inches as a decimal, so 1/8 inch is 0.125 and 3 mm is about 0.118.
• Entering tile size in centimeters or the area in square meters. Tiles are in inches and the area in square feet; 10 m² is about 108 sq ft.
• Using the tile thickness as the joint depth without checking. The depth is how deep the grout actually fills, which can be less than the tile thickness.
• Ignoring waste. The figure is a net amount; mixing losses and uneven tiles mean you need more.
• Assuming that doubling the tile size halves the grout. Tile length and width both matter, and a rectangular tile is not the same as a square one of equal area.