Construction calculator

Tile Calculator

Project area (m²)Coverage per unit (m²)Waste allowance (%)

Required tile units: -

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Calculation explained

How this result was calculated

The formula, your substituted values, and the evaluated result are shown below.

This is a planning estimate. Confirm dimensions, allowances, material specifications, applicable codes, and supplier requirements before purchasing or construction.

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How the Tile Calculator works

Estimate the number of tile units needed from area, unit coverage, and waste allowance.

Before using the result

This is a planning estimate. Confirm dimensions, allowances, material specifications, applicable codes, and supplier requirements before purchasing or construction.

About this calculator

Estimate the number of tile units needed from area, unit coverage, and waste allowance.

Calculator guide

How the tile calculator works

The calculator divides the area you are tiling by the area one unit covers, adds a waste allowance, and rounds up to a whole number, because you can't buy part of a tile or a box:

Units = round up( area (m²) ÷ coverage per unit (m²) × (1 + waste % ÷ 100) )

You choose what the "unit" is. Enter the area of one tile to get a tile count, or the coverage printed on the box to get the number of boxes.

Worked example: a 3.2 m × 2.5 m floor with 600 × 600 mm tiles

Floor area: 3.2 × 2.5 = 8.0 m²
Area of one tile: 0.6 × 0.6 = 0.36 m²
Waste 10%: 8.0 ÷ 0.36 × 1.10 = 24.4, rounded up to 25 tiles
If the box holds 4 tiles (1.44 m²): 8.0 ÷ 1.44 × 1.10 = 6.1, rounded up to 7 boxes

Always work out the box count too. Seven boxes is 28 tiles, which covers the job with a few spares left over.

How much waste to allow

Layout	Suggested waste
Straight lay, simple rectangular room	10%
Brick-bond or offset pattern	10 – 12%
Diagonal or herringbone	15 – 20%
Large-format tiles or lots of cuts around fixtures	15%+

Keep a few spare tiles after the job. If one cracks in five years, the exact batch and shade may no longer be available.

Measuring tips

Split L-shaped or irregular rooms into rectangles and add them up.
For walls, measure each wall's width × tiled height, then subtract windows and doors. Don't subtract small items like power points.
Buy all tiles from the same batch (check the batch or shade code on the boxes). Colour can vary noticeably between runs.

Common mistakes

Entering tile size in millimetres. A 600 mm tile must be entered as 0.36 m² of coverage, not 600.
Using the nominal tile size when the box states an actual coverage. Use the box figure where you have it.
Forgetting skirting tiles, step nosings or niches.

Frequently asked questions

How many 600 × 600 tiles are in a square metre?

1 ÷ 0.36 = 2.78 tiles, so allow about 3 per m² before waste.

How many 300 × 300 tiles are in a square metre?

Exactly 11.1 (1 ÷ 0.09), so allow about 12 per m² with waste.

Do grout joints change the tile count?

Very slightly: a 2–3 mm joint reduces the count by under 1% for large tiles. Ignore it and let the waste allowance cover it. For grout, use the coverage chart on the grout bag for your tile size and joint width.

Written by Sam Alex, civil engineer. About the author