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QuantoObra

Floor Tile Calculator

Enter the room size and your tile to see exactly how many tiles and boxes to buy, plus grout and thinset.

Any surfaceFloor tileWall & backsplash

Results update as you type.

Area

Measure by
ft
ft

Tile

in
in
in

e.g. 1/16, 1/8, 3/16

in

Sets grout depth

%

Set by pattern; adjust if needed

On the box label

Setting materials & prices

$/ft²
lb
$
lb
$

Tiles needed

130tiles

Boxes
13
130 tiles
Area incl. waste
132 ft²
120 ft² net
Grout
8.6 lb
1 bag
Adhesive
95 lb
2 bags

Shopping list

  • 13Boxes of 12 × 12 in tile (10/box)

    130 tiles · 130 ft²

  • 125 lb bag of unsanded grout

    8.6 lb needed

  • 250 lb bag of tile adhesive (thinset)

    94.6 lb needed · 1/4 × 3/8 in square notch trowel

  • 1Tile spacers, sponge & grout float

    Recommended

Add prices below to see a cost estimate.

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How we calculate

area = length × width
tiles = ⌈area × (1 + waste %) ÷ ((tile W + joint) × (tile L + joint))⌉

Grout and thinset follow the same formulas as the main tile calculator.

Floor tiling tips

  • Start the layout from the centre of the room so cut tiles at opposite walls are equal.
  • Large-format tiles (15 in / 38 cm and up) need a flat floor — within 1/8 in over 10 ft.
  • Leave a 1/4 in (6 mm) movement joint at walls, hidden by baseboard.

Frequently asked questions

How many tiles do I need for a 10x10 floor?

With 12 × 12 in tiles and 1/8 in joints, 100 ft² plus 10% waste needs 108 tiles — 11 boxes of 10. With 12 × 24 in tiles it’s about 55 tiles.

What size tile is best for a small bathroom floor?

Larger tiles (12 × 24 in) make small rooms look bigger with fewer grout lines, but need a very flat subfloor. Small tiles or mosaics are better for sloped shower floors.

Do I need a backer board under floor tile?

Over wood subfloors, yes — cement board or an uncoupling membrane. Over a sound concrete slab you can tile directly or use a membrane to bridge cracks.

What trowel size for 12x24 floor tile?

Use a 1/2 × 1/2 in square notch (or 1/4 × 3/8 in with back-buttering) and check coverage by lifting a tile: you want 80%+ contact (95% in wet areas).

Related calculators

Flooring Calculator →

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Tiles, boxes, grout and thinset step by step, with waste by layout and a quick-reference table.

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