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Generator Hut

Tile Calculator

How many tiles and boxes an area needs, at any tile size.

Your measurements

Set to 1 if buying loose.

10% for a straight grid, 15% or more for diagonal and small mosaics.

Tiles required

44tiles

44 tiles — 8 boxes

Area to tile10 ft × 8 ft
80 sq ft
Coverage per tile12 in × 24 in
2 sq ft
With waste allowance+10%
88 sq ft
Tiles required
44 tiles
Boxes to buyat 6 per box
8 boxes

The waste figure matters more for tile than for most materials, because cuts at the edges are unavoidable and a cracked tile mid-job is common. Below 10% you are relying on getting every cut right first time.

Adhesive and grout are separate purchases and depend on tile size, trowel notch and joint width — the coverage figures on those bags are the ones to follow.

Order all boxes from one batch. Shade variation between production runs is normal and shows badly across a floor.

Enter the area and the size of a single tile, and it works out how many you need and how many boxes that is. Waste matters more for tile than almost any other material — every perimeter piece needs a cut, and a tile that cracks on the saw is simply gone.

Why use this tool?

Any rectangular tile

From small mosaics to large-format planks. Enter the dimensions in inches and it derives the coverage per tile itself.

Tiles and boxes both

The tile count is what you check against the layout; the box count is what you actually buy. Set tiles per box to 1 if buying loose.

Realistic waste

Cuts at the edges are unavoidable and breakage is normal. Below 10% you are assuming every cut goes right first time.

Coverage shown per tile

The square footage of a single tile is itemised, which makes it easy to sanity-check against the manufacturer's own figure.

How this tile calculator works

A tile's coverage is its width times its height in inches, divided by 144 to convert to square feet. A 12 by 24 inch tile covers exactly two square feet; a 3 by 6 subway tile covers an eighth of one.

The area is uplifted by the waste allowance and divided by that per-tile coverage, then rounded up. Boxes follow from dividing the tile count by the tiles per carton and rounding up again — two roundings, which is why the supplied quantity can run noticeably above the bare requirement on small jobs.

Grout joints are deliberately not modelled. A typical eighth-inch joint reduces the number of tiles needed by well under one per cent, which is an order of magnitude smaller than the waste allowance sitting on top of it. Subtracting for joints would imply a precision the rest of the calculation does not have.

How to use it

  1. Step 1: Measure the area

    Length and width of the floor or wall. For a wall, measure the section you are tiling rather than the whole wall if it stops partway up.

  2. Step 2: Enter the tile dimensions

    In inches, as sold — a 12x24 tile is 12 and 24. The nominal size is fine; the fractional difference from the actual size is absorbed by the grout joint.

  3. Step 3: Set tiles per box

    Printed on the carton. Use 1 if you are buying individually, which is common for feature tiles and large-format pieces.

  4. Step 4: Choose the waste allowance

    10% for a straight grid on a simple rectangle. 15% or more for diagonal layouts, small mosaics, or a room with many fixtures to cut around.

Example usage

A bathroom floor
An 8 by 10 foot floor is 80 square feet. With 12x24 tiles at 2 square feet each and 10% waste, that is 88 square feet, so 44 tiles — eight boxes of six, supplying 48.
A subway tile splashback
A 3 by 6 inch tile covers 0.125 square feet, so a 30 square foot splashback with 15% waste needs 276 tiles. Small tiles amplify the effect of the waste percentage because each one is a smaller unit of the total.
A diagonal floor
The same 80 square foot bathroom laid diagonally at 15% waste needs 46 tiles rather than 44. The tile count barely moves, but every one of those perimeter cuts is a mitre rather than a straight run.

Frequently asked questions

How much extra tile should I buy?

Ten per cent above the measured area for a straight grid, fifteen or more for diagonal patterns, small mosaics or rooms with lots of fixtures. Tile is the material where running short hurts most, because matching a discontinued batch is often impossible.

Does this account for grout lines?

No, deliberately. A standard grout joint changes the tile count by well under one per cent — far less than the waste allowance — so modelling it would suggest a precision the estimate does not have.

How much adhesive and grout will I need?

That depends on tile size, trowel notch and joint width rather than on area alone, so it is not calculated here. The coverage figures printed on the adhesive and grout packaging are the reliable source.

Can I use this for wall tiles?

Yes. The arithmetic is identical — measure the section of wall you are tiling and enter it as the area. Walls often need a slightly higher allowance because they tend to have more edges and cutouts per square foot.

What if my room is not rectangular?

Split it into rectangles, calculate each, and add the tile counts. Adding the areas first and applying waste once will slightly underestimate, because each sub-area has its own perimeter of cuts.

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