Calculator

Tile Calculator

Tile is sold by the box, not the piece, and the box count depends on more than raw floor area — the layout pattern you choose changes how much of every tile ends up in the scrap pile. A straight (grid) lay wastes relatively little; run the same tile diagonally or in a herringbone weave and the waste percentage roughly doubles, because more tiles get cut at odd angles along the edges.

This calculator takes floor area, tile size, and layout pattern to size the order in boxes, with the waste factor baked in per pattern rather than a single flat percentage for every layout. For the measuring approach on irregular rooms, see how to measure a room for tile; grout and thinset are calculated separately in the grout & thinset calculator since they follow a different formula entirely.

Calculate your quantity

Room length (ft)

Room width (ft)

Coverage per box (sq ft)

Waste factor (%)

10% for straight lay, 15-20% for diagonal or herringbone.

Tile boxes needed

11 boxes

Area: 100 sq ft
Area with waste: 110 sq ft
Waste factor: 10 %

Shopping summary

• 11 box(es) of tile (10 sq ft/box)

This is an estimate — confirm structural work with a professional.

How this calculation works

Base tile count = floor area / area per tile. Waste percentage is added on top: straight lay runs about 10% (mostly edge cuts and breakage allowance), diagonal lay runs 15% (every cut along a wall is now an angled cut instead of a straight one, and angled cuts break more often), and herringbone or other interlocking patterns run 20% or more because most tiles touching a wall or corner require a custom cut.

Grout line width has a smaller but real effect: a wider grout joint (3/8 inch vs 1/16 inch) slightly reduces how many whole tiles fit per square foot, which this calculator also accounts for in the base count.

Common mistakes

Using a flat 10% waste factor regardless of pattern — diagonal and herringbone layouts genuinely need more, not as a safety margin but because the cutting geometry demands it.
Buying tile from different production lots — always check the lot/batch number, since shade variation between lots ('dye lot') can be visible once installed.
Not buying a few extra boxes beyond the waste allowance for future repairs; tile patterns and glazes get discontinued, and matching a cracked tile five years later is often impossible.
Ignoring that large-format tile (24x24 inches or bigger) needs a flatter subfloor and has less forgiveness for waste-percentage errors, since a miscut large tile is expensive to replace.
Not dry-laying a test row before committing adhesive, which is the easiest way to catch a layout or centering problem before it's set permanently.
Rounding the box count down when the calculated need lands just under a full box's coverage, rather than rounding up — a box typically covers a fixed number of whole tiles, and 'almost enough' still means a mid-job store run.

Shopping summary

Order in whole boxes, rounded up from base area plus the pattern-specific waste percentage, all from the same production lot, plus one extra box held back unopened for future repairs — see why you always need 10% extra tile for the fuller case.

Worked example: a 100 sq ft bathroom floor using 12x12 inch tile (1 sq ft each) in a straight lay needs a base count of 100 tiles, plus 10% waste = 110 tiles. If tile is boxed 10 per box, that's 11 boxes. The same room laid on the diagonal needs 100 x 1.15 = 115 tiles, rounding to 12 boxes — one full extra box purely from the layout choice on an identical floor area.

FAQ

Why does herringbone need so much more tile?

Herringbone tiles meet walls and corners at a consistent diagonal angle across the whole field, so almost every border tile requires an angled cut rather than a straight one, and angled cuts have a meaningfully higher breakage rate than square cuts.

Is 10% waste enough for a simple grid layout?

For a rectangular room with a straight lay, yes — 10% comfortably covers edge cuts and normal breakage; irregular rooms with lots of jogs, alcoves, or fixtures (like a bathroom) often run closer to 12-15% even in a straight lay.

Does tile size affect waste percentage independent of pattern?

Somewhat — very large tiles have fewer total cuts but each miscut is more expensive and wastes more material per mistake, while small mosaic tile has many more individual pieces but the sheets themselves are more forgiving of an odd room edge, so the practical waste allowance doesn't move dramatically with size alone the way it does with pattern.

Should grout line width change how many tiles I order?

A wider grout joint slightly reduces the number of whole tiles that fit per square foot compared to a hairline joint, which this calculator's base tile count already accounts for — the effect is usually modest (a few percent) compared to the pattern-driven waste percentage, but it's real on a large floor.