Tile answer guide

How much tile do I need?

Estimate tile order area, tile pieces, boxes, setting materials, and cost from room dimensions, tile size, waste, and carton coverage.

Reviewed - May 18, 2026

Short answer

For a rectangular tile area, multiply length by width, multiply by the number of matching areas, add a waste percentage for cuts and breakage, then divide by tile size or box coverage.

The tile calculator uses that same method to estimate order area, tile pieces, boxes, setting materials, DIY material cost, labor, and contractor total.

Keep floor tile, wall tile, shower tile, and trim pieces separate when the material, tile size, pattern, or box coverage changes.

Use the tile calculator

Tile quantity formula

Calculate net tile area as length x width x number of matching areas.
Add separate rectangles for floors, walls, shower surrounds, niches, and backsplash runs only when they use the same tile and box coverage.
Choose a waste percentage for cuts, broken pieces, pattern matching, and attic stock.
Calculate order area as net tile area x (1 + waste percentage / 100), rounded up to whole square feet.
Divide order area by the selected tile size to estimate tile pieces.
Divide order area by box coverage and round up again so the purchase is in full cartons.
Compare the full-carton purchase quantity with the net tile area so you know how much spare tile remains for repairs.

Quick examples

5 ft by 8 ft bathroom

45 sq ft

Ceramic 12 x 12 tile with 12% waste

12 ft by 10 ft kitchen

135 sq ft

Porcelain 12 x 24 tile with 12% waste

Two 12 ft by 9 ft rooms

249 sq ft

Porcelain 12 x 24 tile with 15% waste

16 ft backsplash run

28 sq ft

3 x 6 ceramic tile, 18 in high, 15% waste

Three 5 ft by 8 ft shower walls

142 sq ft

Porcelain 12 x 24 tile, 18% waste for wet-area cuts

These examples use the current U.S. default tile material, setting-material, labor, tile-size, waste, and full-box rounding assumptions.

Worked example

1 area at 10 ft by 8 ft.

Tile order area

90 sq ft

80 sq ft net area plus 12% waste

Tile pieces

45 tiles

12 x 24 in tile planning size

Boxes

6 boxes

16 sq ft per box

DIY material total

$390–$1,440

Tile plus thinset, grout, spacers, and setting supplies

Contractor total

$1,190–$3,120

Materials plus labor

Starter shopping list

porcelain tile 90 sq ft
Tile pieces 45 tiles
Thinset, grout, spacers, sealer, backer board As needed

This example is generated from the same calculator logic used on the Tile calculator page.

Measuring tile area

Measure the tiled surface, not the whole room, when only part of a floor, wall, backsplash, or tub surround is being tiled.
Break L-shaped rooms, niches, returns, and backsplash runs into rectangles, then add the pieces before applying waste.

Mixed surfaces and layouts

Run separate estimates when a floor, wall, accent band, niche, bullnose, or trim profile uses a different tile, box coverage, or waste percentage.
For visible layouts, dry-fit the first rows from the main sight line so narrow slivers do not force extra cuts after the order is placed.

Waste and tile size

Use a larger buffer for diagonal layouts, small tile, large-format porcelain, stone, fragile pieces, or rooms with many cuts.
Nominal tile size drives the tile-piece count, while box coverage controls how many cartons you buy.

Setting materials

Plan thinset, grout, spacers, sealer, backer board, waterproofing, trim, and movement joints separately from tile pieces.
Wet areas, uneven substrates, and large-format tile can need prep work that changes the cost more than the square footage does.

Common mistakes

Buying exactly the net square footage with no tile waste or attic stock.
Measuring the full room when only a backsplash, shower wall, or partial floor is in scope.
Combining floor tile, wall tile, accent tile, and trim pieces in one estimate when they have different sizes or carton coverage.
Using the tile-piece count but forgetting that tile is usually sold by full boxes.
Leaving thinset, grout, spacers, sealer, backer board, waterproofing, trim, or substrate repair out of the plan.

FAQ

How do I calculate how much tile I need?

Multiply length by width for each tiled area, add the areas together, add a waste percentage, then divide by tile size for pieces or by box coverage for cartons.

How much extra tile should I buy?

Simple tile layouts often use about 10% to 12% waste. Diagonal patterns, small pieces, stone, large-format tile, and rooms with many cuts may need 15% to 20% or more.

Should I calculate tile by pieces or boxes?

Use tile pieces to understand the layout quantity, but use box coverage for the purchase quantity because most tile is bought by full carton.

Can I combine floor and wall tile in one estimate?

Only combine areas that use the same tile, pattern, waste percentage, and box coverage. Run separate estimates for floor tile, wall tile, accent bands, shower niches, and trim when those details differ.

Does tile square footage include grout joints?

For planning, use the nominal tile size and a conservative waste percentage. Exact grout-joint layout can change piece count, especially with small tile, borders, and patterned work.