How many tiles do I need?

Divide the area by the coverage of one tile including its grout joint, then add a waste allowance and round up. The joint matters — a 3 mm gap on a 12-inch tile adds about 2 percent to its footprint.

What grout gap should I use?

Two to three millimetres for rectified tiles, which are cut precisely, and about five for rustic or handmade tiles whose edges vary. A wider joint hides size variation; a narrow one demands consistency.

How much grout will I need?

It depends on joint width, tile size and depth — wider joints and smaller tiles use much more. The estimate here scales with all three, but the coverage figure on the bag for your specific tile size is more reliable.

Should I keep spare tiles?

Yes, a few whole ones. Replacing a cracked tile is easy with a match and effectively impossible without, and tile lines are discontinued faster than most people expect.

Tile Calculator

Tiles, boxes and grout for a floor or wall, from the tile size and area.

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About the Tile Calculator

The tile count is not simply area divided by tile size, because the grout joint adds to the space each tile occupies. A 3 mm joint on a 12-inch tile adds about 2 percent to its footprint, which across a large floor is a full box.

Waste allowance covers cuts at the edges and the tiles that break in handling. Ten percent is right for a straight grid in a simple room; 15 to 20 for a diagonal layout, which cuts every perimeter tile at an angle and leaves unusable offcuts.

Keep a few whole tiles back after the job. A cracked tile is straightforward to replace if you have a match and effectively impossible once the line is discontinued — which happens faster than most people expect.

How it works

Enter the area to tile and the size of a single tile.
Add the grout gap and the waste allowance for cuts.
You get tiles, boxes, grout and a total cost.

Frequently asked questions

How many tiles do I need?: Divide the area by the coverage of one tile including its grout joint, then add a waste allowance and round up. The joint matters — a 3 mm gap on a 12-inch tile adds about 2 percent to its footprint.
How much extra should I allow for tile cuts?: Ten percent for a straight grid in a simple room, and 15 to 20 for a diagonal layout, which cuts every perimeter tile at an angle and leaves offcuts that cannot be used elsewhere.
What grout gap should I use?: Two to three millimetres for rectified tiles, which are cut precisely, and about five for rustic or handmade tiles whose edges vary. A wider joint hides size variation; a narrow one demands consistency.
How much grout will I need?: It depends on joint width, tile size and depth — wider joints and smaller tiles use much more. The estimate here scales with all three, but the coverage figure on the bag for your specific tile size is more reliable.
Should I keep spare tiles?: Yes, a few whole ones. Replacing a cracked tile is easy with a match and effectively impossible without, and tile lines are discontinued faster than most people expect.

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