Home improvement
Tile Calculator
Works tile quantity, where the layout and the substrate both matter.
Result
Thinset and grout quantities depend heavily on tile size, trowel notch and joint width. Large-format tile uses far more thinset per square foot than mosaic; small mosaic uses far more grout.
Get a Free Business AuditHow the calculation works
Area divided by the coverage per box, rounded up to whole boxes, with a waste allowance, plus adhesive and grout quantified from the tile size and joint width. Smaller tiles use more adhesive and grout per unit area; larger tiles use less of both and demand a flatter substrate.
What moves the number
- Tile size and joint width, which set grout quantity.
- Layout pattern and the cuts it forces.
- Substrate flatness, particularly for large format tile.
- Waste from cuts and breakage.
Where this one goes wrong
Large format tile is unforgiving of an uneven substrate, because a tile that cannot flex will lip or crack over a high spot, which means the preparation work is part of the job rather than an optional refinement and the flatness tolerance is specified rather than approximate. Check the substrate before buying the tile. Movement joints are the other requirement people omit, and a tiled area without provision for movement cracks along a line of its own choosing.
Before you quote
- Check substrate flatness against the tile size's requirement.
- Include movement joint provision in the layout.
- Quantify adhesive and grout from tile size and joint width.
Where the rules come from
Questions
About this calculator
Why does large format tile need a flatter floor?
Because a large tile cannot flex over a high spot, so it lips at the edge or cracks. The flatness tolerance is specified rather than approximate, which makes substrate preparation part of the job rather than an optional refinement.
How much grout and adhesive do I need?
It depends on the tile size and joint width, not just the area. Smaller tiles use more of both per square foot because there are more joints and more bedding depth variation, which is why the calculation needs the tile dimensions.
Do I need movement joints?
In most tiled areas of any size, yes, and at changes of plane and around the perimeter. A tiled area without provision for movement cracks along a line of its own choosing, which is both a cosmetic and a water ingress problem.
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How to use this calculator
- Area length (ft) (ft). Enter your own figure; the page starts at 10 ft.
- Area width (ft) (ft). Enter your own figure; the page starts at 8 ft.
- Coverage per box (sq ft) (sq ft). Enter your own figure; the page starts at 15 sq ft.
- Waste allowance (%). 12% for straight lays, 20% for diagonal.
- Cost per box ($). Enter your own figure; the page starts at $38.
The result updates as you type, so you can try a figure, see what it does to boxes needed, and change it back. Nothing you enter is sent anywhere or saved.
A worked example
These are the figures the calculator opens with. Every number in the results column below is produced by the same calculation the page runs, so you can follow it through before putting your own figures in.
What goes in
| Input | Value |
|---|---|
| Area length (ft) | 10 ft |
| Area width (ft) | 8 ft |
| Coverage per box (sq ft) | 15 sq ft |
| Waste allowance | 12% |
| Cost per box | $38 |
What comes out
| Result | Value |
|---|---|
| Boxes needed main result | 6 |
| Area | 80.0 |
| Area including waste | 89.6 |
| Estimated material cost | $228 |
| Thinset bags (50 lb) | 1 |
| Grout (lb, approx.) | 45 |
For 80.0 sq ft plus 12% waste you need 6 boxes, costing about $228.
How sensitive the answer is
Holding everything else steady and changing only cost per box, this is what happens to boxes needed. It is worth knowing which of your inputs the answer actually hinges on, and which barely move it.
| Cost per box ($) | Boxes needed |
|---|---|
| $19 | 6 |
| $28.5 | 6 |
| $38 example above | 6 |
| $57 | 6 |
| $76 | 6 |
Every other input is held at the example value while this one changes, which is not how a real job behaves. Treat it as a guide to which number matters most, not as five separate quotes.
What each figure means
- Area length (ft) (ft)
- Measured in ft, starting at 10 ft.
- Area width (ft) (ft)
- Measured in ft, starting at 8 ft.
- Coverage per box (sq ft) (sq ft)
- Measured in sq ft, starting at 15 sq ft.
- Waste allowance (%)
- 12% for straight lays, 20% for diagonal.
- Cost per box ($)
- A money amount, starting at $38.
What the results tell you
| Result | What it is |
|---|---|
| Boxes needed | The headline result. A number. |
| Area | A decimal figure. |
| Area including waste | A decimal figure. |
| Estimated material cost | A money figure. |
| Thinset bags (50 lb) | A number. |
| Grout (lb, approx.) | A number. |
Keep going
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