Tile Calculator
How many tiles and boxes you need.
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Avoid a mid-job trip to the shop. Enter your floor or wall area and the size of the tiles, add a waste margin, and this calculator tells you exactly how many tiles and boxes to buy.
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How Many Tiles? — The Quick Answer
Divide the area to be tiled by the area of one tile, then add 10% for cuts and breakages. A 10 × 8 ft floor (80 sq ft) with 12 × 12 inch tiles (1 sq ft each) needs about 80 tiles, or 88 with waste.
Shortcut
Tiles = (area ÷ tile area) × (1 + waste %)
Tiles per square foot by size
| Tile size | Area per tile | Tiles per sq ft |
|---|---|---|
| 12 × 12 in | 1 sq ft | 1.0 |
| 12 × 24 in | 2 sq ft | 0.5 |
| 6 × 6 in | 0.25 sq ft | 4.0 |
| 18 × 18 in | 2.25 sq ft | 0.44 |
| 24 × 24 in | 4 sq ft | 0.25 |
Tiles are almost always sold by the box, not individually, so this calculator also works out how many boxes to buy based on your tiles-per-box figure.
How It Works
The Formulas
Area ÷ tile area
Formula
Tiles = (floor area ÷ tile area) × (1 + waste) Boxes = ⌈tiles ÷ tiles per box⌉
Variables
Floor or wall area
Length × width of the surface to be covered, in square feet.
Area of one tile
Tile size in inches, divided by 144 to convert to square feet (since 1 sq ft = 144 sq in).
Waste allowance
Extra percentage for cuts, breakages, and odd corners. 10% is standard; diagonal or herringbone patterns may need 15%.
Note: Grout lines add a little to the spacing but are generally ignored in estimates like this — the waste allowance more than covers the difference.
Worked Example: A 10 × 8 ft Floor with 12-Inch Tiles
From area to boxes
Find the floor area
10 × 8 = 80 sq ft
Divide by one tile's area
12 × 12 in = 1 sq ft → 80 tiles
Add waste
+10% = 88 tiles
Round up to boxes
88 ÷ 10 per box = 9 boxes (90 tiles)
Reference Guide
| Tile size | Area per tile | Tiles per sq ft |
|---|---|---|
| 12 × 12 in | 1 sq ft | 1.0 |
| 6 × 6 in | 0.25 sq ft | 4.0 |
| 12 × 24 in | 2 sq ft | 0.5 |
| 18 × 18 in | 2.25 sq ft | 0.44 |
| 24 × 24 in | 4 sq ft | 0.25 |
Waste, Layout & Batch Matching
The planning that makes a tiling job work
10% is standard for a straight grid, covering cuts at edges, breakages, and future repairs. Diagonal and herringbone layouts generate more offcuts, so budget 15% or more there.
Best for: Setting a sensible waste allowance
A straight grid wastes the least; diagonal and herringbone patterns create many angled offcuts and raise waste. Decide the layout before you calculate quantities, not after.
Best for: Matching the waste figure to your pattern
Tiles vary slightly in colour and size between production batches. Buy all your tiles (including waste) in one go from the same batch, since a later top-up from a different batch can show a visible step across the floor.
Best for: Avoiding an unfixable colour mismatch
How Many Tiles Do You Need?
Working out tiles is simple arithmetic — divide the area to cover by the area of one tile — but the planning around it is where jobs go wrong. You always buy more than the bare area to cover cuts, breakages, and future repairs: about 10% for a straight grid, 15% or more for diagonal or herringbone layouts that create more offcuts. Because tiles are sold by the box and vary slightly between production batches, it's important to buy everything in one go from the same batch. This calculator takes your floor area and tile size, adds your waste allowance, and converts the total into the number of boxes to buy.
Key Features
💡 Pro Tips
- →Decide your layout before calculating — diagonal and herringbone need a bigger waste allowance than a straight grid.
- →Buy all your tiles at once from one batch, and keep a few spares (ideally a full box) for future repairs.
- →Grout lines barely change the count; the waste allowance comfortably covers the difference.
- →For rooms with alcoves or lots of cuts, lean toward the higher end of the waste range.
Common Mistakes
Buying exactly the floor area in tiles
With no waste allowance, the first few breakages or edge cuts leave you short — and a top-up may come from a mismatched batch. Always add 10% or more.
Ignoring the layout's effect on waste
A diagonal or herringbone pattern creates far more angled offcuts than a straight grid. Using a grid-level allowance for a diagonal floor underestimates the tiles needed.
Not matching the batch
Colour and size drift between production runs. Buying more later from a different batch can leave a visible seam across the floor that's essentially impossible to fix.
Research & Citations
Sources and standards referenced for the factual claims on this page
- [1]
The Tile Association (TTA) (2023). Guidance on tile fixing and wastage allowances. tiles.org.uk.
Industry guidance on tiling wastage and batch (shade) matching.
View source - [2]
ANSI / Tile Council of North America (TCNA) (2022). Handbook for Ceramic, Glass, and Stone Tile Installation. TCNA.
Standards for tile installation, including shade variation.
View source
This calculator is a reference tool, not a substitute for professional advice. Verify important health, financial, legal, or safety decisions with a suitably qualified professional.
Last updated: October 7, 2026
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Frequently Asked Questions
How do I calculate how many tiles I need?
Divide your floor area by the area of a single tile. For an 80 sq ft floor and 12 × 12 in tiles (1 sq ft each), that's 80 tiles. Add 10% waste to get 88 tiles, so you'd buy enough boxes to cover that.
How much waste should I allow for tiles?
10% is a safe default for a straightforward grid layout. Increase it to 15% for diagonal or herringbone patterns, and more if the room has lots of corners, alcoves, or pipes to cut around.
How many tiles are in a box?
It varies by manufacturer and tile size — commonly 10 for 12 × 12 in tiles, fewer for large-format tiles. Check the box label and enter the number in the calculator for an accurate box count.
Should I buy extra tiles?
Yes, beyond the immediate waste allowance. Keeping a few spare tiles lets you replace cracked or stained ones later — matching a batch after the fact is often impossible. Many tilers recommend an extra box.