Tile Calculator

For 100 sq ft with 12×12 in tiles and 10% waste, you need about 110 tiles. Divide the total area by the area of one tile (tile width × tile length in inches ÷ 144), then add your waste percentage.

Add 10% for straight, square layouts. Use 15–20% for diagonal patterns, patterned tile, or rooms with lots of cuts and angles. Always buy from the same production lot — colours vary between batches.

One 50 lb bag of thinset covers roughly 40–50 sq ft with a standard 1/4 in square-notch trowel. Large-format tile (over 15 in) needs a bigger notch, so coverage drops to about 30 sq ft per bag.

Grout coverage depends on tile size and joint width. For 12×12 in tile with 3/16 in joints, plan on roughly 0.5 lbs per sq ft — about one 25 lb bag per 50 sq ft. Smaller tiles or wider joints use more grout.

3/16 in is the most common for standard ceramic floor and wall tile. Use 1/8 in for natural stone and polished porcelain. Large-format rectified tile can go as tight as 1/16 in. Wider joints (1/4 in) suit handmade or rustic tile.

Use sanded grout for joints 1/8 in or wider. Use unsanded grout for joints narrower than 1/8 in, for glass tile, and for polished or softer stone — sand can scratch delicate surfaces.

Yes, on floors and wet areas (showers, tub surrounds). Cement backer board — or an uncoupling membrane — gives tile a stable, moisture-resistant base. Tick the checkbox and the calculator adds the sheets to your list.