Tile Calculator

How to use this calculator

1. Choose Floor or Wall, and Metric or Imperial units.
2. Enter the length and width of the area to tile, and any untiled area to exclude.
3. Enter the tile length and width.
4. Choose how your tiles are packaged, and enter the tiles per box or the box coverage.
5. Pick a layout for a suggested waste allowance, and add a spare percentage if you want one.
6. Optionally add adhesive coverage or consumption details, and material costs.
7. The calculator estimates the tiles, boxes and adhesive bags to buy.

What do I need to enter?

• Surface type — Floor or Wall. It only changes the helper text about adhesive beds; it does not change the figures.
• Measurement units — Metric or Imperial. Dimensions, areas and adhesive weights switch together.
• Length and Width — the area to tile. Each must be greater than zero and no more than 100 m (or the equivalent).
• Area to exclude — optional untiled area, such as a bath or fixed units, subtracted from the area to tile. It must be smaller than the area to tile.
• Tile length and Tile width — each greater than zero and no more than 3 m.
• How your tiles are packaged — Tiles per box, Coverage per box, or I only need tile count. The first two also give a box count.
• Cuts and wastage — a layout preset sets the waste: 10% Straight / simple grid, 12% Offset / running bond, 15% Diagonal, 20% Herringbone / patterned. Custom takes 0% to 50%.
• Spare tiles — optional extra percentage for future repairs, 0% to 20%.
• Tile adhesive — optional, with three choices. Do not calculate adhesive leaves it out. Coverage per bag takes the area one bag covers, from the packaging. Consumption per area + bag size takes the Consumption rate (weight of adhesive per area) and the Bag weight, and works out the bags from those. Each value must be greater than zero. Once adhesive is on, Adhesive contingency adds 0% to 25% to the net area to tile; it is separate from the tile waste and spares.
• Material costs — optional. Choose a price per box or per tile, then add an adhesive price per bag and other materials if you want them in the subtotal.

What do the results show?

• Tiles to buy — the main figure: the order area divided by one tile, rounded up, including waste and spares.
• Gross area, Area excluded and Net area to tile— the area you entered, what you took off, and what is left to cover.
• Tiles before waste — the whole tiles needed to cover the net area with no allowance added.
• Boxes and Coverage purchased — shown when you enter tiles or coverage per box: whole boxes to buy and the area they cover.
• Adhesive bags — shown when adhesive is on: whole bags for the net area plus contingency.
• Estimated materials subtotal — shown when a price is on: tiles, adhesive and other materials added together.

How is the number of tiles calculated?

The calculator finds the net area to tile, then works out how many tiles cover it before adding a waste allowance for cuts and breakages and an optional spare allowance. The result is rounded up to a whole tile, and then to a whole box if you buy tiles by the box.

Example: a 4 m × 3 m floor, 600 × 600 mm tiles, 10% waste, 10 tiles per box

1. 4 × 3 = 12 m² net area, with nothing excluded.
2. Each tile covers 0.6 × 0.6 = 0.36 m².
3. 12 × 1.10 = 13.2 m² after a 10% waste allowance, with no spare tiles added.
4. 13.2 ÷ 0.36 = 36.67, which rounds up to 37 tiles to buy.
5. 37 ÷ 10 = 3.7, which rounds up to 4 boxes — 40 tiles purchased in total.

Why is adhesive calculated separately from tile waste?

Tile waste and spare tiles allow for cuts, breakages and future repairs in the tiles themselves. An offcut from a cut tile does not usually need its own extra bed of adhesive, so sizing adhesive from the larger tile order area would overstate what is needed. Instead, adhesive is calculated from the net area to tile plus its own contingency percentage, which you set independently — typically a smaller allowance for spreading losses and an uneven substrate rather than for cutting waste.

Metric and imperial tile measurements

The calculator converts every measurement into a single internal area in square metres before showing results in the selected measurement system, so metric and imperial results can never disagree. Imperial mode uses feet and inches for dimensions, square feet for area, and pounds for adhesive weight.

Example: a 10 ft × 12 ft floor, 12 in × 12 in tiles, 10% waste, 10 tiles per boxgives 120 ft² of net area, 132 tiles to buy, and 14 boxes.

How much tile waste should I allow?

A waste allowance helps cover cuts, breakages, pattern matching and small mistakes. The layout presets in the calculator — straight or simple grid, offset or running bond, diagonal, and herringbone or patterned — are common starting points, not guarantees. A room with many corners, pipework or a large-format tile can need a higher allowance regardless of the layout.

What this calculator does not cover

This is an order-planning estimate only. It does not produce a cutting plan, a tile layout, a grout estimate, an adhesive, trowel, substrate or waterproofing recommendation, a manufacturer installation instruction, a labour quote, or a building or safety compliance result. Complex layouts, uneven surfaces, cuts, movement joints, waterproofing and substrate preparation can all change what is needed — check tile and adhesive packaging, manufacturer data sheets and installation requirements before buying or fitting materials.

Related tools

Painting the rest of the wall rather than tiling all of it? See the Paint Coverage Calculator.

Frequently asked questions