Tile Calculator
How many tiles, boxes, grout, and trim pieces you need — with NTCA-aligned pattern waste factors. Free, browser-only, no signup.
1. Surface area
2. Tile size
3. Installation pattern (NTCA waste factor)
- Surface area: 100 sq ft
- Tile area: 144 sq in (1.00 sq ft)
- Tiles before waste: 100 tiles
- Waste multiplier: 1.10× (10%) (NTCA standard)
- Tiles with waste: 110 tiles, rounded up
- Boxes: ceiling(110 tiles ÷ 10 per box) = 11
How the tile calculator works
Tile quantity is driven by three numbers: surface area, tile size, and the pattern's waste factor. The math is simpler than it looks. Take the area, divide by one tile's area, multiply by 1 plus the waste factor, and round up. The optional grout and trim layers then sit on top of the tile count using their own formulas.
The NTCA waste factor table
Waste percentages come from the Tile Council of North America (TCNA) and the National Tile Contractors Association (NTCA) installation guidelines, where they form the standard reference cited across the tile industry.
| Pattern | Waste | Why |
|---|---|---|
| Straight grid | 10% | Perpendicular cuts at room edges only |
| Brick / staggered | 12% | Slight stagger increases offcuts at row ends |
| Diagonal | 15% | Angled cuts at every wall |
| Herringbone | 18% | Angled offcuts rarely match another position |
| Mosaic / complex | 20% | Highest cut frequency, many small pieces |
Sanded vs Unsanded grout
Joint width determines the grout type. Sanded grout contains fine sand aggregate that fills volume and prevents shrinkage cracking — it is required for joints 1/8 in (3.2 mm) or wider. Unsanded grout is used for joints narrower than 1/8 in, where sand particles would not fit and could scratch polished tile faces (especially marble or glass).
The grout volume formula is the industry standard used by MAPEI and Custom Building Products:
Grout volume per sq ft = (Joint width / Tile length + Joint width / Tile width) × Tile thickness × Density constant
The calculator applies this formula and converts to pounds, then divides by your selected bag size and rounds up. A buffer is included for waste during mixing and application.
Common tile sizes reference
| Type | Common sizes | Typical use |
|---|---|---|
| Subway | 3×6, 2×6, 4×8, 6×12 in | Backsplash, shower walls, kitchen accents |
| Hexagonal | 2", 4", 6", 12" | Vintage bathroom floors, modern accent walls |
| Square floor | 12×12, 18×18, 24×24 in | General floor tile, entryways |
| Large format | 24×48 in or larger | Modern open floors, minimal grout lines |
| Mosaic sheet | ~12×12 in sheets (1.0–1.15 sq ft) | Shower niches, decorative bands, small areas |
Pattern decision tips
- Straight grid: cleanest look, lowest waste, easiest installation. Default for most projects.
- Brick / staggered: subway tile classic, adds visual interest with minimal extra waste.
- Diagonal: visually expands small rooms, but waste jumps to 15%.
- Herringbone: high-end visual, 18% waste, requires skilled installer (cuts at every edge).
- Mosaic / complex: highest waste at 20%, accent areas only unless budget allows.
Privacy
Everything runs in your browser. Dimensions, tile choices, grout settings, and cost estimates are never sent to any server. Inputs save only to local browser storage so the form remembers your last entry. Open developer tools and check the Network tab — nothing leaves your machine while you use this calculator.
Source notes
Waste factors per NTCA / TCNA installation guidelines. Grout volume formula per MAPEI and Custom Building Products manufacturer documentation. Tile size standards per ANSI A137.1 and major manufacturer references (Daltile, Mineral Tiles, Apollo Tile). Coverage rates are approximate and assume professional installation conditions; actual usage varies by jobsite, mixing technique, and waste.