How many 12x12 tiles do I need for 100 square feet?

A 12 × 12 in tile covers just over one square foot with its joint, so 100 square feet takes about 95 tiles — order 105 with a 10 percent cut allowance.

How much waste should I add for tile?

Add 10 percent for a straight lay, and 15 percent for diagonal, herringbone, or rooms with many cuts. Keep a few spares for future repairs.

Materials

Tile Calculator

Calculate tiles, boxes, thinset and grout for floors, walls and backsplashes.

100% free to useNo sign-up requiredImperial & metric units

How many tiles do I need?

To find how many tiles you need, divide the area by the coverage of one tile including its grout joint. A 12 × 12 inch tile with a 1/4 inch joint covers about 1.04 square feet, so a 100 square foot floor takes roughly 96 tiles — order 106 with a 10 percent cut allowance, all from one dye lot.

Inputs

Area lengthft

Area widthft

Tile size

Nominal tile face in square inches, before the grout joint.

Grout joint

Tiles per boxcount

Waste allowanceApplied to material quantities

Results

Tiles Needed

Add 10–15% for cuts

Boxes

Area

40 sq ft

Thinset

1 50 lb bags

Grout

24 lb

Sanded, by joint width

Estimates update instantly as you type. Confirm against local code before ordering materials.

Tile math looks simple until the grout joint gets involved. A 12 by 12 inch tile with a quarter-inch joint does not cover one square foot, it covers slightly more, and across a whole floor that difference decides whether the last box gets opened or the job stalls waiting on a dye-lot match. This free tile calculator folds the joint into the coverage of every tile, then converts your area into tiles, boxes, thinset bags, and grout in one pass.

Cuts are the other half of the story. Every wall the field runs into produces offcuts, and diagonal or patterned layouts produce more. Order with a 10 percent allowance for straight lays and 15 percent for diagonals and herringbone, and keep the spares — a repair tile from the same dye lot is worth far more than the shelf space it takes.

How tile quantity is calculated

The area to be tiled is divided by the coverage of a single tile, including the grout joint on two sides. Box counts come from dividing total tiles by the tiles per box, and thinset and grout scale from the covered area and joint size.

Tiles = Area ÷ ((Tile W + Joint) × (Tile L + Joint))

Tiles per 100 square feet

Approximate tile counts with a 1/4 inch grout joint, before waste.

Tile size	Coverage each	Tiles / 100 sq ft
3 × 6 in (subway)	0.14 sq ft	709 tiles
6 × 6 in	0.27 sq ft	369 tiles
12 × 12 in	1.04 sq ft	96 tiles
12 × 24 in	2.06 sq ft	49 tiles
24 × 24 in	4.08 sq ft	25 tiles

Add 10 percent waste for straight lays and 15 percent for diagonal or patterned layouts.

How to use it

1Enter the length and width of the area in feet.
2Pick your tile size and grout joint width.
3Read the tile count, boxes, thinset bags and grout instantly.
4Add 10% waste for straight lays, 15% for diagonal or patterned layouts.

Key terms explained

Grout joint: The gap between tiles, filled with grout. Wider joints reduce tile count slightly and increase grout usage significantly.
Dye lot: The production batch of a tile. Color and shade vary between lots, so the whole order should come from one lot.
Thinset: The cement-based adhesive bedding the tile. A 50 lb bag covers roughly 85 to 95 square feet with a 1/4 inch trowel.
PEI rating: A wear rating from 1 to 5. Floors need PEI 3 or higher; wall-only tile is often PEI 1 or 2.

Worked examples

Bathroom floor

A 5 ft × 8 ft bathroom in 12 × 12 in tile needs about 39 tiles, or 43 tiles once a 10 percent cut allowance is added.

Kitchen backsplash

A 12 ft × 1.5 ft backsplash in 3 × 6 in subway tile takes roughly 128 tiles plus waste for the cut courses.

Pro tips from the field

1Buy the entire order from a single dye lot, including the waste allowance, returns from a new lot will not match.
2Dry-lay a row in both directions to balance the cuts at the walls before spreading any thinset.
3Large-format tile (any side over 15 inches) needs a flatter substrate and a larger trowel; both change material usage.
4Unsanded grout is for joints under 1/8 inch; sanded grout for anything wider.

Common mistakes

Forgetting the grout joint, which shrinks each tile’s effective coverage.
Ordering exact counts with no cut allowance, then failing to match dye lots later.
Using wall-rated tile on floors where a harder PEI rating is required.

Where it gets used

Bathroom floors and walls

Count tiles, thinset and grout for full bathroom renovations in one estimate.

Kitchen backsplashes

Size subway tile orders where cut courses dominate the count.

Whole-floor installs

Estimate large-format floor tile with box counts ready for the flooring supplier.

Frequently asked questions

Free Tile Calculator for Floors & Walls

Tile is sold by the box but ordered against an area, and grout joints, cuts and dye lots all conspire against exact counts. This free tile calculator converts your floor, wall or backsplash dimensions into tiles, boxes, thinset bags and grout so the whole order lands at once.

Choose your tile size and joint width, then add a cut allowance that matches your layout — diagonal patterns and small rooms burn noticeably more tile than a straight lay in an open floor.