Tile, Grout & Mortar: Calculators, Diagrams & Guides

Q: How much tile should I order beyond the room measurement?

Ten percent for straight layouts, 15 for diagonal or patterned installs, and consider rounding up a further box on natural stone where breakage and shade-matching matter. Ordering the buffer up front keeps every tile in one dye lot — a matched replacement box later is never guaranteed. The tile calculator converts area to boxes with the pattern factor applied. The layout pattern diagram shows how pattern drives waste.

Q: How much thinset do I need per square foot?

It depends on the trowel, which depends on the tile: a ¼×¼ square notch covers roughly 60 to 70 sq ft per 50 lb bag, while the ½×½ notch large-format tile demands covers nearer 30 to 40. The mortar calculator pairs tile size to notch per TCNA guidance and outputs whole bags, including back-butter allowance for tile over 15 inches. The trowel coverage diagram shows how notch size sets the mortar bed.

Q: How do I know how much grout to buy?

Grout volume is geometry: (tile length + width) ÷ (length × width) × joint width × joint depth × density. Doubling the joint width doubles the grout; thicker tile deepens every joint. The grout calculator runs the formula from your exact tile and joint dimensions and outputs pounds, sized to the boxes grout is actually sold in. The grout coverage diagram shows why small tile needs far more grout.

Q: What size grout joint should I use?

ANSI A108.02 sets the floor at 1/16 inch for rectified tile, with 3/16 the common floor-tile default and ⅛ typical on walls. The practical rule: the joint must absorb the tile’s size variation — calibrated rectified tile can run tight; handmade and natural stone need wider joints to keep lines reading straight over a full wall. The grout type selector diagram matches joint width to unsanded, sanded, or epoxy grout.

Q: Do I need to waterproof behind shower tile?

Yes — tile and grout are not waterproof; the assembly behind them is what keeps the wall dry. Code and TCNA methods require a waterproof membrane (sheet or liquid-applied) over an appropriate backer board in wet areas. Cement board alone lets vapor through. The wet-wall assembly diagram shows the full stack from stud to tile face.

4 calculators · 16 diagrams · 2 guides

Tile jobs are a chain of small quantities that each punish a bad guess: tiles per box with pattern waste, thinset bags by trowel notch, grout pounds that swing wildly with joint width and tile thickness, and the waterproofing behind wet walls that no one sees until it fails. The four calculators in this hub cover the chain — floor and wall tile counts, backsplash takeoffs with outlet cutouts, grout weight from the exact joint geometry, and mortar coverage by trowel size and tile format.

The diagrams hold the trade knowledge: layout starting lines that keep cut tiles balanced at the walls, lippage control on large-format tile, the wet-wall assembly from stud to surface, which trowel notch pairs with which tile size, and why big tile demands back-buttering and a ½-inch notch while mosaic runs happy on a ¼-inch V.

The math follows the TCNA Handbook and ANSI A108/A118 standards — the same documents inspectors and manufacturer warranties reference — including the ANSI A108.02 grout-joint minimums and mortar coverage requirements (80 percent dry areas, 95 percent wet). All four calculators are free with no signup, and each tool links to its full installation guide for the how, not just the how-much — layout, membrane, and grouting sequence included.