Tile Flooring Calculator
Buying tile by the box means you’re always rounding up, so it pays to get the math right before checkout. Enter your room dimensions and this calculator returns boxes needed, thinset bags, and total cost with waste built in.
Total area of doors, windows or other openings to subtract.
Covers cuts, breakage and layout waste. 5–10% is normal.
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Ordering tips
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Coverage & waste
Material profile
Start with the room’s gross square footage (length × width), subtract any openings like a closet footprint you won’t tile, and add a waste percentage for cuts around edges and pattern layout. Divide that net area by the coverage of one box of your chosen tile, then round up since tile only sells by the full box. Thinset needs are estimated separately based on total coverage area and standard bag coverage.
Trowel Size by Tile Size
Notch size on your thinset trowel controls how much mortar transfers to the floor and how well the tile bonds. Bigger tile needs a bigger notch.
| Tile Size | Trowel Notch | Typical Coverage |
|---|---|---|
| 6×6 in | 3/16 in V-notch | Higher coverage per bag |
| 12×12 in | 1/4 in square-notch | Moderate coverage per bag |
| 12×24 in and larger | 1/2 in square-notch | Lower coverage per bag |
Tile box coverage by size
| Type | Coverage / unit | Size | Best for |
|---|---|---|---|
| 12×12 in tile (12 sqft/box) | 12 sq ft | 12 in x 12 in | Standard floor tile |
| 12×24 in tile (16 sqft/box) | 16 sq ft | 12 in x 24 in | Modern plank-style layout |
| 6×6 in tile (10 sqft/box) | 10 sq ft | 6 in x 6 in | Bathrooms, backsplashes |
How to calculate how many tile boxes you need
- Measure the room’s length and width to get gross square footage.
- Subtract any areas you won’t tile, like a closet or cabinet footprint.
- Add waste 12% is typical for a straight layout; more for diagonal or herringbone patterns.
- Choose a tile and divide net area by that tile’s coverage per box.
- Round up to the next full box, then estimate thinset bags for the total area.
Worked example
A 12 ft x 10 ft room with 12×12 in tile and 12% waste runs through the calculator like this.
- Room size (gross area)12 ft x 10 ft = 120 sq ft
- Openings0 sq ft
- Net area120 sq ft
- Waste allowance12%
- Tile selected12×12 in (12 sq ft/box)
- Boxes needed12 boxes
- Thinset needed3 bags
- Total material cost12 boxes ($456) + 3 thinset bags ($54) = $510
Tile Sizes and Box Coverage
| Tile Size | Coverage per Box | Best Use |
|---|---|---|
| 6×6 in | 10 sq ft/box | Bathrooms, backsplashes |
| 12×12 in | 12 sq ft/box | Standard floor tile |
| 12×24 in | 16 sq ft/box | Modern plank-style layout |
Ordering Tile
Order every box you need in a single purchase and confirm the dye lot number matches across all boxes before you leave the store or the delivery arrives. If you’re not sure exactly how much waste your layout will generate, round up to the next full box rather than ordering the bare minimum. Reordering later, even from the same product line, risks a visible shade difference that shows up under raking light.
- Match dye lot numbersacross every box so color stays consistent across the room.
- Round up per boxboxes don’t split, so always round the fractional box up.
- Buy thinset and grout separatelythese aren’t included in the tile box count.
- Keep one spare boxfor future repairs, since matching tile later gets harder as lots age out.
Common mistakes
- Not accounting for pattern wastediagonal, herringbone, and large-format layouts cut more waste than a straight grid; bump your waste allowance up for these.
- Ignoring dye lot numberstile color can shift slightly between production runs, so buy all boxes from the same lot number when possible.
- Using the wrong trowel notchan undersized notch starves the tile of mortar and leads to hollow spots and adhesion failure.
- Skipping substrate prepplywood subfloors need an uncoupling or crack-isolation membrane in most cases; tiling straight over an unprepped subfloor risks cracked grout lines.
What this calculator assumes
Adjust your result if your project differs from these.
- Tile coverage is based on the box coverage figures for the material you select.
- Waste percentage accounts for cut tiles at room edges and normal breakage.
- Thinset bag count is estimated from total net coverage area, not a per-tile calculation.
- Layout is assumed to be a standard grid or offset pattern, not a complex mosaic.
- Pricing uses the per-box and per-bag costs you enter.
Common questions
How much extra tile should I buy?
12% is a reasonable default for a straight layout. Go up to 15-20% for diagonal, herringbone, or large-format tile with fewer full pieces per box.
Do I need to buy tile all at once?
Yes if possible. Tile color and shade can vary between dye lots, so buying everything in one order (from the same lot number) avoids visible mismatches.
How many bags of thinset do I need?
It depends on trowel notch size and tile size, but this calculator estimates bags from your total coverage area using standard bag coverage figures.
Should I subtract closets and cabinets from the area?
Yes, subtract any footprint you won’t actually tile, like a closet floor or built-in cabinet base, before adding waste.
What's the difference between thinset and mastic?
Thinset is cement-based and required for wet areas and most floor tile. Mastic is a pre-mixed adhesive limited to dry wall applications.
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materialcalculate.com/tools/tile-flooring-calculator/
Project
| Wall size | — |
| Openings deducted | — |
| Net area | — |
| Material | — |
| Waste allowance | — |
Shopping list
| Units needed | — |
| Mortar / mix | — |
| Estimated total cost | — |
Notes
Estimate generated by materialcalculate.com. Confirm quantities with your supplier before ordering.