ContractorHandbook

How Many 12x12 Tiles for 100 Square Feet?

Tiles needed

108 tiles

100 square feet, 12 by 12 tile, an eighth inch joint, 15 tiles a box, 10 percent waste.

It does not stop at a number.

When the figures look right, the tile material list downloads as a real PDF with your business details on it, built inside your own browser. Nothing you type is uploaded anywhere.

waste10%floor area, sq ftone tile, width x height, plus the grout jointarea / coverage of one tile = tiles, then round to whole boxes
A tile calculator is a division, but the divisor is not the tile size on the box. The grout joint makes each tile cover slightly more than its nominal face, and boxes only come whole, so the answer rounds twice.

How that number is worked out

These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.

  • Area to tile100 sq ft
  • Tile width12 in
  • Tile length12 in
  • Tile thickness0.3125 in
  • Grout joint0.125 in
  • Tiles per box15 each
  • Waste allowance10 %

Tiles needed108 tiles

Area with 10% waste110 sq ft
Coverage of one tile1.021 sq fttile plus one joint
Tiles per square foot0.98
Boxes at 15 per box8
Thinset, 50 lb bags2about 60 sq ft per bag at this tile size
Grout5.6 lbsold in 10 and 25 lb boxes
Backer board, 3 by 5 sheets7

The material list this produces

Tile, boxes8
Thinset mortar, 50 lb bags2
Grout, lb6
Tile spacers, each216
Cement backer board, 3 x 5 sheets7
Backer board screws, each280

Waste allowance compared

Waste is the only input here you choose rather than measure, and it is the one that decides whether the job finishes on a Saturday or on the following Saturday.

Waste allowanceTiles neededBoxes at 15 per box
5%103 tiles7
10%108 tiles8
15%113 tiles8
20%118 tiles8

What else matters here

A hundred square feet of 12 by 12 does not take 100 tiles. With a normal eighth inch joint each tile occupies 12.125 inches square, which is 1.021 square feet of floor, so the bare floor wants 98 and the order with waste wants 108.

That is 8 boxes at 15 tiles a box. Boxes vary, so check the count on yours before you order, because a box of 12 by 12 can hold anything from 11 to 17 depending on the maker and the thickness.

Thinset comes to 2 bags at the 60 square feet a quarter by three eighths notch gives you under a tile this size. Grout is small, under 6 pounds, because a 12 inch tile has relatively little joint per square foot compared with anything smaller.

What this calculator assumes

  • The tile count is worked out from the space one tile actually occupies, which is the tile plus one grout joint on two sides, not the tile on its own. On a 12 by 24 with an eighth inch joint that difference is about one percent, and on a mosaic it is far more.
  • 10 percent waste suits a straight lay in a square room. A diagonal or herringbone lay wastes 15, and a room full of jogs, niches and closets can reach 20.
  • Grout is figured geometrically: the joint volume is the space around each tile times the tile thickness, converted at 105 pounds per cubic foot, which is where sanded grout lands once mixed. Manufacturer coverage charts vary, so treat this as the order quantity and not the gospel.
  • Thinset coverage follows the trowel, and the trowel follows the tile: about 85 sq ft from a 50 lb bag with a quarter inch notch under small tile, 60 under 12 inch, and 40 under large format where the notch grows and the tile gets back buttered.

Questions people ask

How many 12x12 tiles are in 100 square feet?

98 to cover the bare floor at an eighth inch joint, and 108 once 10 percent waste is on it. Eight boxes at 15 a box.

How much waste should I add?

Ten percent for a straight lay in a square room, fifteen for a diagonal or a cut up bathroom, twenty for herringbone. Under ten leaves nothing for a bad box or a broken tile, and both happen.

Should I buy extra tile?

Buy the whole job plus the waste in one order. Tile is fired in batches and the shade moves between batches, so a replacement box bought next spring will read as a patch from across the room. Keep the offcuts too, because a cracked tile three years from now is a lot easier to match from your own attic than from a supplier.

Different numbers?

The tile calculator takes any dimensions you like and hands back the same list.

Other common sizes