TILE QUANTITY

Measure the area length and width in feet. For an irregular floor (L-shaped bathroom, kitchen with peninsula), use the L-shape toggle and enter the cutout. Pick the tile size from the dropdown — the calculator already knows tiles per square foot for each common nominal size (4×4 = 9 tiles/ft², 12×12 = 1 tile/ft², 24×24 = 0.25 tiles/ft²).

Choose the layout: straight (grid pattern) adds 10% waste; diagonal or offset patterns add 15%. The result is the total tile count rounded up. Tiles are typically sold by the box (10–20 tiles per box for 12×12s, fewer for larger formats), so check the box count when buying — you almost always need to round up to the next full box.

For an 8 × 10 ft bathroom floor (80 ft²) using 12×12 tiles, straight pattern:

Tiles per ft²: 1.0. Waste factor: 1.10. Tiles needed: 80 × 1.0 × 1.10 = 88 tiles.

If the boxes hold 10 tiles each, you need 9 boxes (90 tiles). If 12 per box, 8 boxes (96 tiles).

At $2–$5/ft² for ceramic or $5–$10/ft² for porcelain, materials cost $200–$800. Add thinset mortar ($30/bag, ~50 ft² coverage = 2 bags), grout ($25/bag, covers ~150 ft² for a ⅛-inch joint = 1 bag), tile spacers, and rental of a wet saw ($50/day) for a DIY install.

Switching to a diagonal layout: 80 × 1.15 = 92 tiles → still 9–10 boxes. The waste increase is real but small at this size; bumps up sharply on bigger floors with lots of edges.

Underordering for diagonal or herringbone. The 15% factor in the calculator is the minimum. For a true herringbone with 45° cuts at every edge, plan on 18–22% waste, especially in narrow rooms.

Buying tile from different lots. Color and shade vary slightly between manufacturing lots. Always check the lot number on each box and buy all your tile from the same lot. Stores can usually pull from a single lot if you ask up front.

Forgetting cement board, thinset, and grout in the budget. The tile is often less than half the total materials cost. Cement board ($10–$15 per 3×5 sheet), thinset ($30/bag), grout ($25/bag), spacers, and corner trim add up to $100–$300 even on a small bathroom.

Skipping the dry layout. Lay the tiles out without thinset first to confirm the cuts at the edges and around fixtures. A small shift in starting position can move all your edge cuts from awkward 1-inch slivers to half-tiles, which look much cleaner.

Tiles per ft²: 4×4 = 9 · 6×6 = 4 · 12×12 = 1 · 12×24 = 0.5 · 18×18 = 0.44 · 24×24 = 0.25.

Waste factor: 10% straight, 15% diagonal/offset. Bump to 18–22% for true herringbone or rooms with lots of cuts.

Thinset coverage: 1 bag of 50lb modified thinset covers about 50 ft² with a ¼-inch notched trowel. Larger format tiles need a ½-inch trowel and use closer to 30 ft² per bag.

Grout coverage: 1 bag covers ~150 ft² of 12×12 with ⅛-inch joints, much less for smaller tiles or wider joints.

Always order at least 1 extra box beyond the calculated count and keep it sealed for future repairs — tile lines get discontinued constantly.