How many 12 × 12 tiles in 100 square feet?

One hundred tiles cover exactly 100 sq ft, so with a 10 % allowance buy 110, which is 11 boxes of 10.

How much extra tile should I buy?

Ten percent for a straight lay in a square room, fifteen for a diagonal layout, a busy pattern or a room with many corners and fixtures. Plus a spare box.

How much thinset and grout?

A 50 lb bag of thinset covers roughly 75 sq ft with a ¼ in square-notch trowel, less for large tile. A 25 lb bag of grout covers about 100 sq ft of 12 in tile with ⅛ in joints; small mosaics use far more.

Tile calculator

Form 36 · Materials estimateFigures checked 2026-09-04

US customary

Measurements

Length(ft)

Width(ft)

Areas this size

What you need

Quantity · Amount

01Area to tile10 × 8 ft80 sq ft
02Tiles at 12 × 12 in88 sq ft including 10 % cuts88
03Boxes of 10$3 per sq ft9 boxes$264
04Thinset mortar, 50 lb bagsabout 75 sq ft per bag with a ¼ in square-notch trowel2 bags$40
05Grout, 25 lb bagsabout 100 sq ft of 12 in tile with ⅛ in joints1 bag$22

Total, materials$326

Keep one full box spare for repairs; dye lots change.
Large-format tile needs a bigger trowel and more thinset: halve the coverage for tiles over 15 in.

The material

Tile length(in)

Tile width(in)

Tiles per boxPrinted on the box with the square feet it covers

Cutting allowance(%)Straight lay 10 %; diagonal or many cuts 15 %

Prices — put in what you were quoted

Tile price($ per sq ft)Ceramic $1–4, porcelain $3–8, stone $6–20 per sq ft

Thinset($ per bag)A 50 lb bag covers about 60–95 sq ft with a ¼ in trowel

Grout($ per bag)A 25 lb bag covers about 100 sq ft of 12 in tile with ⅛ in joints

Total, materials88 tiles$326

Where these figures come from

Thinset and grout coverages are the bag-chart figures for a ¼ in trowel and 12 in tile with ⅛ in joints; they change with tile size and joint width.
Prices are typical US retail figures at the date on this sheet.

Type the area and the tile size. The sheet counts tiles and boxes with a cutting allowance (10 % straight, 15 % diagonal), then adds thinset and grout from the coverage on the bag. Buy all boxes from one lot so the shade matches.

Worked examples

Bathroom floor 8 × 10 ft, 12 in tile: 9 boxes — boxes of 10, about $326 in materials.
Kitchen backsplash 3 × 12 ft, 3 × 6 subway: 8 boxes — boxes of 44, about $161 in materials.

How it is worked out

Tiles = area × (1 + cuts) ÷ (tile length × width ÷ 144), rounded up. Boxes = tiles ÷ tiles per box, rounded up. Thinset bags = area ÷ 75. Grout bags = area ÷ 100.

The figures behind it

Thinset and grout coverages are the bag-chart figures for a ¼ in trowel and 12 in tile with ⅛ in joints; they change with tile size and joint width.
Prices are typical US retail figures at the date on this sheet.

Every figure here is an estimate. Materials vary with moisture, compaction and product; order a little extra and confirm quantities with your supplier.

Questions people ask

How many 12 × 12 tiles in 100 square feet?: One hundred tiles cover exactly 100 sq ft, so with a 10 % allowance buy 110, which is 11 boxes of 10.
How much extra tile should I buy?: Ten percent for a straight lay in a square room, fifteen for a diagonal layout, a busy pattern or a room with many corners and fixtures. Plus a spare box.
How much thinset and grout?: A 50 lb bag of thinset covers roughly 75 sq ft with a ¼ in square-notch trowel, less for large tile. A 25 lb bag of grout covers about 100 sq ft of 12 in tile with ⅛ in joints; small mosaics use far more.

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