How Much Tile Do I Need?

The number of tiles you need depends on your area, tile size, and lay pattern. Add 10% for straight lay or 15% for diagonal to account for cutting waste.

The quick formula

Tiles = ceil(Area × (1 + waste%) ÷ sq ft per tile)

Tile size reference

Tile size	Sq ft per tile	Tiles per 100 sq ft (straight)
4” × 4”	0.111	1,109 tiles
6” × 6”	0.250	440 tiles
3” × 6” subway	0.125	880 tiles
12” × 12”	1.000	110 tiles
18” × 18”	2.250	49 tiles
24” × 24”	4.000	28 tiles

Includes 10% waste for straight lay.

Waste by lay pattern

Pattern	Waste	When
Straight (parallel to walls)	10%	Most floors and walls
Diagonal (45°)	15%	Feature areas, small bathrooms
Herringbone / pattern	15%	Complex cuts at edges

Thinset and grout estimates

Material	Coverage	Notes
Thinset — 50 lb bag	~40 sq ft	3/8” notched trowel, flat surface
Grout — 10 lb bag (sanded)	~50 sq ft	1/8” joint, 12×12 tile

Grout coverage drops significantly with larger joints or smaller tiles (more joint area per sq ft).

How to measure

Floor: length × width in feet
Shower walls: each wall separately (height × width), then add together
Backsplash: measure each section (length × height), add sections
Irregular spaces: use the Irregular shape option in the Tile Calculator

Use the Tile Calculator for your exact area, tile size, and lay pattern.

Frequently Asked Questions

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

You need 110 tiles for 100 sq ft with straight lay (10% waste). Each 12×12 tile covers exactly 1 sq ft, so 100 sq ft × 1.10 = 110 tiles. For diagonal lay, use 115 tiles (15% waste).

How do I calculate tile for a bathroom floor?

Measure the bathroom length × width in feet. Subtract the toilet flange and vanity footprint if desired. Add 10% waste for straight lay or 15% for diagonal. Divide by the sq ft per tile for your tile count.

How many boxes of tile do I need?

It depends on how many tiles come in a box. Divide your total tile count by tiles per box, then round up. Large format tiles (18×18, 24×24) often come 3–6 per box; smaller tiles may come 20+ per box.

How much thinset do I need?

A 50 lb bag of thinset mortar covers approximately 40 sq ft using a 3/8" notched trowel. For 100 sq ft, you need about 3 bags. Coverage varies with trowel size and substrate flatness.

How much grout do I need for tile?

Grout coverage depends on tile size and joint width. As a rough estimate for 1/8" joints and 12×12 tiles, a 10 lb bag covers about 50 sq ft. Use sanded grout for joints wider than 1/8", unsanded for narrower.