How Many Tiles Do You Need?
Calculate the number of tiles needed for floors, walls, and backsplashes. Includes grout lines, cuts, and waste factor.
How to Calculate Tile Quantity
The basic formula: Area (sq ft) ÷ Tile size (sq ft) × Waste factor = Tiles needed. Always round up and buy extra. A standard 12×12 tile covers 1 sq ft. A 12×24 tile covers 2 sq ft. Grout lines slightly reduce the tile coverage area, but this is usually absorbed by the waste factor.
Waste Factors by Pattern
Straight grid: 5-10% waste (minimal cuts). Brick offset: 10% (half-tiles at edges). Diagonal 45°: 10-15% (triangle cuts at all edges). Herringbone: 15-20% (most cuts, most complex). The waste factor accounts for cutting, breakage, and future replacements. Always keep 2-3 extra tiles after installation for future repairs.
Mortar and Grout Estimates
A 50-lb bag of thinset mortar covers approximately 40-50 sq ft with a 1/4" × 3/8" trowel (standard for most floor tiles). Larger tiles need a larger trowel notch, reducing coverage. A 25-lb bag of sanded grout covers approximately 75-100 sq ft for 12×12 tiles with 1/8" grout lines. Use unsanded grout for grout lines 1/8" or narrower.
The most common DIY tiling mistake: not back-buttering large-format tiles (12×24 and bigger). Apply thinset to both the floor AND the back of the tile, then comb one surface. This ensures 95%+ mortar coverage, preventing hollow spots that crack under foot traffic.
