Tile Calculator
Calculate tiles needed, boxes, grout weight, and thinset bags for floor and wall tile installations. Six tile size presets (4×4 to 24×24 plus 12×24 plank) plus custom dimensions. Four patterns with auto-fill waste percentages. Grout formula calibrated against Custom Building Products TDS-360 within ±4%.
Results
Estimates only. Grout coverage formula calibrated against Custom Building Products Polyblend Plus TDS-360 within ±4%. Thinset coverage varies with trowel size and substrate; check the bag label.
How to use this calculator
- 01Pick Floor or Wall to set the default tile thickness — 5/16″ (8 mm) for floor, 1/4″ (6 mm) for wall. Your override is preserved across mode switches.
- 02Pick a Shape and enter your dimensions. Rectangle for typical rooms; Custom Area for L-shapes or summed multi-room totals.
- 03Pick a Tile Size. The six presets auto-fill dimensions and recompute tiles-per-box from a 12 sq ft (1.1 m²) baseline. Pick Custom for non-standard sizes — the formula handles non-square (12×24 plank, 4×16 subway).
- 04Pick a Pattern. Waste auto-fills (10% straight, 12% brick, 15% diagonal, 20% herringbone). Bump up if your project has many cuts or you’re a first-time installer.
- 05Set Joint Width (1/8″ / 3 mm is standard) and pick your Grout Bag Size. Optionally enter Price per Box for cost estimation. Read the results — Tiles Needed includes waste, Boxes Needed is what to order, Grout Bags rounds up from the calibrated formula output.
Understanding the math
Three steps. First, tile count from area and tile dimensions:
tiles = ⌈(area × 144 ÷ tile_area_in²) × (1 + waste%)⌉
Second, grout via the half-perimeter rule. Each tile is allocated half its perimeter joint (the other half belongs to the adjacent tile). Joint depth equals tile thickness:
grout_lb = tiles × jw × th × (perimeter ÷ 2) × density ÷ 1728
where jw = joint width (in), th = tile thickness (in), perimeter = 2 × (tile_length + tile_width), density = 110 lb/ft³ (sanded grout, calibrated against Custom Building Products Polyblend Plus TDS-360 coverage chart, page 9). Third, thinset by tile-size coverage:
thinset_bags = ⌈area ÷ coverage_per_bag⌉
where coverage_per_bag is 50 sq ft for tiles ≤ 6 in, 75 for 6-12 in, 90 for 12-24 in, and 60 for tiles > 24 in (medium-bed mortar). Worked example: 120 sq ft (11.1 m²) of 12×12 in (30×30 cm) tile, 3/8″ thickness, 1/8″ joint, straight pattern, 10% waste, 25 lb bags. Tiles = ⌈120 × 1.10⌉ = 132. Grout per tile = 0.125 × 0.375 × 24 = 1.125 in³; total = 120 × 1.125 / 1728 × 110 = 8.6 lb → ⌈8.6/25⌉ = 1 × 25-lb bag. Thinset = ⌈120/90⌉ = 2 bags.
Tile size reference
Tile count and grout weight per 100 sq ft (≈ 9.3 m²) at the standard 1/8″ (3 mm) joint, computed at render time from the calculator’s formula so the values match calculator output exactly. Smaller tiles have more linear feet of joint per square foot of installation, so they need more grout.
Computed for 100 sq ft at 1/8″ joint width.
| Tile Size | Tiles / 100 sq ft | Grout (lb) at 1/8″ joint |
|---|---|---|
| 4×4 in / 10×10 cm | 900 | 14.3 lb |
| 6×6 in / 15×15 cm | 400 | 9.5 lb |
| 12×12 in / 30×30 cm | 100 | 7.2 lb |
| 18×18 in / 45×45 cm | 44 | 4.8 lb |
| 24×24 in / 60×60 cm | 25 | 3.6 lb |
Pattern reference
Industry-standard waste percentages for the four most common tile patterns. Higher cut overhead means more partial-tile waste at edges and corners.
| Pattern | Waste % | Best for |
|---|---|---|
| Straight | 10% | Clean, modern, and forgiving installs — most common |
| Brick | 12% | Subway tile and casual, classic kitchens / baths |
| Diagonal | 15% | Visual interest in small rooms — extra cuts at edges |
| Herringbone | 20% | Premium, intricate look — high cut overhead |
Frequently asked questions
How many tiles do I need for my project?
Tile count = (project area × 144) ÷ (tile length × tile width), where dimensions are in inches and project area is in square feet. Multiply by 1 + (waste % ÷ 100) and round up. For 120 sq ft (11.1 m²) of 12×12 in (30×30 cm) tile at 10% waste: (120 × 144) ÷ 144 = 120 tiles × 1.10 = 132 tiles. The calculator above handles the math automatically — pick a preset or enter custom dimensions.
How much grout do I need?
Grout weight depends on tile size, joint width, and joint depth. Smaller tiles have more linear feet of joint per square foot of installation, so they need more grout. The calculator uses the half-perimeter rule (volumePerTile = jointWidth × jointDepth × perimeter ÷ 2) calibrated against Custom Building Products Polyblend Plus TDS-360 within ±4%. For 100 sq ft (9.3 m²) of 12×12 in (30×30 cm) tile with 1/8″ (3 mm) joints and 3/8″ (10 mm) thickness: about 7 lbs (3.2 kg) of sanded grout — roughly one 25-lb bag covers 350 sq ft.
What's the difference between sanded and unsanded grout?
Sanded grout contains silica sand and is required for joints 1/8″ (3 mm) or wider — the sand prevents shrinking and cracking in wider joints. Unsanded grout has no sand filler and is used only for joints 1/16-1/8″ (1.5-3 mm) — sand would scratch glossy or polished tile in narrow joints. Sanded is denser (≈110 lb/ft³ / 1,760 kg/m³); unsanded is slightly less. The calculator uses sanded density (the dominant case) — output is within 5% for unsanded too.
How much waste should I add for tile?
Industry rule of thumb: 10% for straight pattern, 12% for brick (offset by half tile), 15% for diagonal (45-degree rotation, more edge cuts), 20% for herringbone (alternating perpendicular planks, very high cut overhead). The calculator pre-fills these when you pick a pattern. Bump up another 5% for small bathrooms with many obstacles (toilet base, vanity, shower curb) or if you're a first-time DIY installer. Cuts go wrong; better to have one extra box than to wait three weeks for a re-order.
What's the difference between pattern types (straight, brick, diagonal, herringbone)?
Straight is grid-aligned — every tile lines up corner-to-corner with its neighbors. Brick offsets every other row by half a tile width — classic subway look. Diagonal rotates the entire pattern 45 degrees relative to the room walls — adds visual interest in small rooms. Herringbone alternates perpendicular planks in a V-pattern — premium and intricate, but the highest cut overhead because every edge tile needs angled cuts. Match pattern to your tile shape: subway tiles look best in brick; large-format porcelain in straight; planks in herringbone.
How much thinset / mortar do I need?
Thinset coverage varies by tile size because the trowel size scales up. For floor tiles ≤ 6×6 in (15×15 cm): one 50 lb (22 kg) bag covers ~50 sq ft (4.6 m²). For 6-12 in (15-30 cm): ~75 sq ft (7 m²) per bag. For 12-24 in (30-60 cm): ~90 sq ft (8.4 m²). For tile larger than 24 in (60 cm), use medium-bed mortar — coverage drops to ~60 sq ft (5.6 m²) per bag because the trowel notch is bigger. The calculator uses the larger tile dimension to bucket coverage automatically.
What's the standard grout joint width?
1/8″ (3 mm) is the most common and works for nearly any tile. Smaller (1/16″ / 1.5 mm) for rectified porcelain where tile edges are perfectly straight and the joint is mostly cosmetic. Larger (3/16-1/4″ / 5-6 mm) for cement bodies, terra cotta, or any tile with non-uniform edges where the joint compensates for variation. Wider joints are more forgiving for DIY installs but use more grout. The calculator handles 1/16-1/2″ (1.5-13 mm).
How many tiles come in a box?
Industry baseline is ~12 sq ft (1.1 m²) per box, regardless of tile size — so you get more tiles in a box of small tiles than large tiles. 4×4 in (10×10 cm): ~108 tiles per box. 12×12 in (30×30 cm): ~12 tiles. 24×24 in (60×60 cm): ~3 tiles. The calculator auto-fills tiles-per-box from a 12 sq ft baseline, but check your actual product label and override if different — premium and commercial tiles have non-standard box sizes.
Can I use tile on walls and floors?
Yes, but pick the right product. Floor tile must be rated for foot traffic (PEI 3 or higher); wall tile is usually PEI 0 or 1 (won't survive on a floor). Floor tile is typically thicker (5/16-3/8″ / 8-10 mm) for impact resistance; wall tile is thinner (1/4″ / 6 mm). Many porcelain products are rated for both. The calculator's Application toggle (Floor / Wall) only changes the default thickness — your selected tile just needs to match the application.
Can I use this calculator for metric measurements?
Yes — pick Metric in the unit selector at the top of the calculator and inputs switch to meters, centimeters, and millimeters. Tile dimensions are in cm (5 cm = 2 in, 30 cm = 12 in, etc). Joint width and tile thickness are in mm (3 mm = 1/8 in). Grout weight output is in kg; thinset bags default to 22 kg (the metric equivalent of 50 lb). Tile sizes auto-convert (12×12 in → 30×30 cm). Your unit choice persists across pages and tabs via localStorage.
Related calculators
Estimates only. Grout coverage varies with installation practices and jobsite conditions; calibrated against Custom Building Products Polyblend Plus TDS-360 (Page 9) coverage chart within ±4% across 4×4, 6×6, 12×12, and 24×24 tile sizes at 1/8″ joint. Thinset coverage varies with trowel size and substrate flatness — check the bag label and add 10-15% for poor substrates. TakeoffCalc is not responsible for material over- or under-orders.