Grout Calculator

Estimate the pounds of grout to fill the joints between tiles. Bigger tiles and narrower joints need less grout.

How the Math Works

The Grout Calculator uses the formula vol/ft² = 144 × (L+W)/(L×W) × joint × depth to determine material needs. Here, L and W represent tile dimensions in inches, while 'joint' and 'depth' are the grout gap width and thickness in inches. The 144 factor converts square inches to square feet. The term (L+W)/(L×W) calculates the perimeter-to-area ratio, accounting for how joint length changes with tile size. Multiplying by joint width and depth gives the cross-sectional area of grout per linear inch of joint, scaled appropriately for practical volume measurements in cubic feet.

Practical Applications

To apply this calculator, first measure your tile length and width in inches, then determine the gap width between tiles (joint) and desired grout depth. Input these values into the formula or calculator interface. For example, 12-inch tiles with 1/8-inch joints and 1/4-inch depth would yield: 144 × (12+12)/(12×12) × (1/8) × (1/4) = 1.5 cubic feet per 100 square feet of tile. Always round up to the nearest half-gallon when purchasing grout, and consider a 10-15% surplus for waste and irregular joints.

Day-to-Day Use

This calculator prevents costly mistakes in everyday tiling projects by ensuring you buy exactly the right amount of grout. Whether you're renovating a bathroom, installing kitchen backsplashes, or laying new flooring, accurate estimates save money and reduce trips to the hardware store. It eliminates guesswork when comparing different tile sizes and patterns, helping you plan projects efficiently and avoid running out of grout mid-job or ending up with excess material that could crack or discolor over time.

Worked example

120 ft² of 12×12 in tiles, 3/8 in thick, 1/8 in joints ≈ 0.59 lb/ft² → ~71 lb of grout.

FAQ