Tile Calculator

Enter the area of a floor or wall and the size of the tile going on it to get the exact tile count with waste built in, a rough grout estimate, and total project cost.

For personal planning and general reference — verify important results when needed.

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Typical: 10% simple, 15–20% complex layouts

Select a calculation type, enter your values, and click Calculate to see how many tiles you need, coverage area, or total cost with step-by-step solutions.

The math behind a tile order

Tile count comes down to one division: how many tile-sized rectangles fit into the area being covered. The wrinkle is that real jobs never use every tile whole — cuts around edges, doorways, and fixtures waste partial tiles constantly — which is why a waste percentage gets added on top of the raw division rather than treating the exact count as the shopping list.

Exact tiles = Area (in²) ÷ Tile area (in²)

Tiles to buy = ⌈Exact tiles × (1 + waste %)⌉

A 200 ft² room with 12 × 12 in tiles (1 ft² each) needs 200 exact tiles. Add a 10% waste allowance: 200 × 1.10 = 220 tiles, rounded up to whatever whole number that already is. That 20-tile buffer covers the pieces that get cut down to fit an edge, plus a few spares in case of breakage.

How much waste to plan for

A simple straight (grid) layout in a rectangular room can often get by with 10% waste, since most cuts are large, usable pieces along one or two edges. A diagonal layout, a herringbone or basketweave pattern, or a room with lots of jogs, niches, and fixtures pushes that closer to 15-20%, because more of the cuts end up small and unusable elsewhere. Buying too little tile mid-project is a bigger problem than buying slightly too much — dye lots vary between production runs, so a second order months later may not match the first exactly.

Estimating grout alongside the tile

Grout fills the joints between tiles, and while the exact amount depends on tile size, joint width, and grout depth, a workable rule of thumb for planning purposes is about 1 pound of grout per 10 square feet of tiled area.

Grout (lbs) ≈ Area (ft²) ÷ 10

200 ft² ÷ 10 = 20 lbs of grout

Larger tiles with fewer, narrower joints use noticeably less grout per square foot than small mosaic tiles with dense joint lines, so treat this as a ballpark for a typical floor or wall tile rather than an exact figure for every tile size.

Planning the layout before the first tile goes down

Starting a tile layout from a room's corner tends to leave one edge with a full row of tiles and the opposite edge with an awkward sliver — visually lopsided even though the tile count is identical. Working out from the center of the room instead, and adjusting the starting point so the cut tiles at both edges come out roughly equal width, is standard practice for a cleaner-looking finished floor. Either way, partial tiles at the edges still count toward the total tile quantity, so the layout choice affects appearance, not how many tiles to buy.

Measuring the space first

If you still need to work out the room's area — especially for an irregular shape — the square footage calculator covers rectangles, circles, triangles, and more, and its result feeds directly into the area field here.

Frequently Asked Questions

How many tiles do I need for a floor or wall?

Divide area to cover by area of one tile (including grout gaps if the tool supports it). Round up and add waste for cuts and breakage.

How much extra tile should I order?

Add 10–15% for straight layouts; 15–20% for diagonal or complex patterns. Keep spare boxes for future repairs — dye lots can differ.

Do grout lines change tile count?

Yes. A 12-inch tile with ⅛-inch grout joints covers slightly less than 1 sq ft per tile. Include joint width in layout calculations.

How do I handle partial tiles at edges?

Plan layout from the room center so cut tiles at walls are equal width. Partials still count toward total tile quantity.

How do I use this tile calculator?

Enter room dimensions, tile size, grout width, and layout style, then click Calculate. Tile count, boxes, and area with waste appear in the results.

How much grout do I need for a tile job?

A rough rule of thumb is about 1 pound of grout per 10 square feet of tile, though the real number shifts with tile size and joint width, since larger tiles need less grout per square foot than a mosaic with many narrow joints. Treat the estimate as a starting point and round up when buying.

Should I buy tile by the box or by the piece?

Tile is almost always sold by the box, with a fixed number of pieces (or square footage) per box printed on the label. Once you know how many individual tiles you need, divide by the box coverage and round up, since a store generally will not split a box for a fractional amount.

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