Tile Calculator

About Tile Calculator

How the Tile Count Is Calculated

Tiles needed = Room area / (Tile width + Grout gap) x (Tile height + Grout gap), rounded up, then multiplied by 1 + waste%. Grout gaps slightly enlarge each tile's effective footprint, which reduces the raw tile count before waste is added.

Step	Formula	Example (100 sq ft room, 12x12 in tiles, 1/8 in grout)
Effective tile size	Tile dimension + Grout gap	12 + 0.125 = 12.125 inches each way
Effective tile area	Effective width x Effective height	12.125 x 12.125 = 147.02 sq in = 1.021 sq ft
Tiles needed (exact)	Room area / Effective tile area	100 / 1.021 = 97.9 tiles
Tiles needed (rounded up)	Ceiling of exact count	98 tiles
With 10% waste	Tiles x 1.10	98 x 1.10 = 107.8, rounded to 108 tiles
Boxes needed	Tiles / Tiles per box (rounded up)	108 / 12 = 9 boxes

Common Tile Sizes

Size (inches)	Area per Tile (sq ft)	Common Name	Typical Use
3 x 6	0.125	Subway tile	Kitchen backsplash, bathroom walls
4 x 4	0.111	Standard small tile	Accent walls, shower niches
6 x 6	0.25	Small square	Bathroom floors, shower walls
12 x 12	1.0	Standard square	Floors, walls, most versatile size
12 x 24	2.0	Large format rectangle	Modern floors, feature walls, makes small rooms look bigger
18 x 18	2.25	Large square	Large floor areas, open-plan rooms
24 x 24	4.0	Extra large	Commercial floors, large modern bathrooms
2 x 2 mosaic sheet	~1.0 (per sheet)	Mosaic	Shower floors, decorative accents

Waste Percentage Guide

Tile waste comes from cuts at edges, around obstacles, and breakage during installation. The right waste factor depends on the layout pattern:

Layout Pattern	Recommended Waste %	Why
Straight lay (grid)	10%	Minimal cuts; edges only
Brick / running bond (offset)	10-12%	Slightly more edge cuts from the offset
Diagonal (45 degree)	15%	Every edge piece is a triangle cut
Herringbone	15-20%	Complex angles, many small cuts
Complex pattern / mixed sizes	20%+	Multiple tile sizes, more breakage risk
Rooms with many obstacles	15%+	Pipes, toilets, cabinets all require cuts

Grout Gap Sizes

Gap Width	Typical Use	Notes
1/16 inch (1.5 mm)	Rectified (precision-cut) tiles	Very tight; requires perfectly flat substrate
1/8 inch (3 mm)	Standard wall and floor tiles	Most common residential gap
3/16 inch (5 mm)	Handmade or irregular tiles	Wider gap accommodates size variation
1/4 inch (6 mm)	Outdoor tiles, rustic styles	Allows for thermal expansion

Wider grout gaps reduce the number of tiles needed slightly because each tile's effective coverage area increases. The calculator accounts for this automatically.

Cost Estimation

Enter a price per tile and tiles per box to get a total cost estimate and box count. The calculator supports multiple currencies. Remember to budget for additional costs beyond tiles:

Item	Typical Cost Range	Notes
Tiles	$1-15 per sq ft	Ceramic cheapest, natural stone most expensive
Thinset mortar	$15-30 per 50 lb bag	One bag covers ~50-75 sq ft
Grout	$10-25 per 25 lb bag	One bag covers ~75-100 sq ft depending on tile size and gap
Backer board (wet areas)	$10-15 per 3x5 sheet	Required in showers and tub surrounds
Professional installation	$5-15 per sq ft	Varies by region and complexity

Tile Selection Tips

Consideration	Recommendation
Small bathroom	Larger tiles (12x24) reduce grout lines and make the space feel bigger
Shower floor	Small mosaic tiles (2x2 or smaller) are easier to slope toward the drain
Kitchen floor	Porcelain or ceramic 12x12 or larger; avoid polished finishes (slippery when wet)
Backsplash	Subway tile (3x6) is classic; measure the exact wall area to avoid over-ordering
Outdoor patio	Porcelain rated for outdoor use (frost-proof, slip-resistant)

Worked Example: 10x12 ft Bathroom Floor

A bathroom measuring 10 ft by 12 ft has a total floor area of 120 sq ft. Using 12x24 inch large-format porcelain tiles with a 1/8 inch grout gap and 10% waste:

• Effective tile size: (12 + 0.125) x (24 + 0.125) = 12.125 x 24.125 = 292.5 sq in = 2.031 sq ft per tile
• Raw tile count: 120 / 2.031 = 59.1 tiles
• With 10% waste applied before rounding: 59.1 x 1.10 = 65.0, rounded up to 65 tiles
• At $4 per tile: 65 x $4 = $260 in tiles
• Boxes (8 tiles per box): ceil(65 / 8) = 9 boxes

Homewyse's January 2026 cost guide puts basic tile floor installation at $16.38 to $20.21 per square foot for labour and materials combined, so a full professional job on this bathroom would run roughly $1,966 to $2,425. The raw tile cost is usually 20-30% of the total - most of the spend is labour, substrate prep, thinset, grout, and trim pieces.

What Does Tile Cost in 2026?

Tile-only prices span a wide range depending on material. Angi's 2026 ceramic tile data lists glazed ceramic at $4-$15 per sq ft and unglazed ceramic at $3-$35 per sq ft. Installed ceramic tile typically lands at $12-$45 per sq ft once labour is included. Labour alone ranges from $5-$22 per sq ft in 2026, with metropolitan areas like New York, San Francisco, and Boston running 30-50% above the national average.

Tile Material	Price per sq ft (US, 2026)	Notes
Ceramic (standard)	$1-$15	Budget-friendly, glazed finish for moisture resistance
Porcelain	$3-$20	Denser, lower water absorption, good for outdoor use
Natural stone (travertine, slate)	$5-$30	Needs sealing; each piece varies in colour and texture
Marble	$10-$50+	Premium look; sensitive to acids and stains
Glass mosaic	$10-$40 per sheet	Decorative use; backsplashes and feature walls
Quarry tile	$2-$8	Unglazed, dense, used in commercial kitchens and patios

UK pricing is broadly similar once converted. Wickes and Topps Tiles list porcelain floor tiles from around £15-£50 per square metre as of April 2026, which works out to roughly £1.40-£4.65 per sq ft for budget-to-mid-range stock.

Common Tiling Mistakes That Waste Money

Mistake	Why It Matters	Fix
Ordering exact tile count with no waste	Even a straight lay needs cuts at walls and obstacles; one broken tile can halt the job	Always add 10% minimum; more for patterns and older buildings with uneven walls
Mixing dye lots mid-job	Tiles from different batches can show subtle colour differences, very visible after grouting	Buy all tiles in a single order and check the batch number on each box
Forgetting trim and edge pieces	Bullnose, quarter-round, and transition strips are sold separately	Count linear feet of exposed edges and add trim pieces to the order
Ignoring substrate condition	Tiles over flexing plywood or cracked concrete will crack; backer board or uncoupling membrane is often required	Check Tile Council of North America (TCNA) handbook requirements for wet areas and subfloor spans
Wrong tile rating for location	Wall tiles installed on floors crack under load; polished tiles in showers become slip hazards	Check the PEI rating (1-5) and DCOF (slip resistance, minimum 0.42 for wet floors per ANSI A137.1)
Skipping a dry layout	Pattern issues like slivers along one wall only show up once you start laying tiles	Lay tiles loose across the floor before mixing thinset to find the best starting point

PEI and Slip-Resistance Ratings

The PEI (Porcelain Enamel Institute) rating tells you where a tile can safely be used. It runs 0 to 5, measuring the tile's resistance to surface wear from foot traffic.

PEI Rating	Traffic Level	Suitable Use
PEI 0	No foot traffic	Walls only
PEI 1	Very light	Bathroom walls, light-use residential floors (bare feet)
PEI 2	Light	Residential floors except kitchens and entryways
PEI 3	Moderate	All residential floors including kitchens, light commercial
PEI 4	Moderate to heavy	All residential, medium commercial (offices, hotels)
PEI 5	Heavy	All residential, heavy commercial (shopping centres, airports)

ANSI A137.1 sets a Dynamic Coefficient of Friction (DCOF) of 0.42 or higher for level interior floors that could become wet, such as entryways, kitchens, and bathrooms. Manufacturers publish this value on their technical data sheet for every tile line.

Ordering Checklist Before You Buy

Before placing the order, run through each item to avoid an extra trip to the store mid-install:

• Measure length and width of each room and add them up - count alcoves, closets, and under-cabinet runs separately
• Subtract fixed features that will not be tiled under (kitchen island footprints, built-in cabinets)
• Pick the layout pattern first, because it drives the waste percentage (straight 10%, diagonal 15%, herringbone 20%)
• Confirm tiles-per-box with the supplier; this affects how many boxes round up
• Add trim pieces (bullnose, quarter-round) for exposed edges
• Budget for thinset (~1 bag per 50-75 sq ft) and grout (~1 bag per 75-100 sq ft)
• Keep one full box unused after the job for future repairs - matching tiles years later is often impossible

Before buying tiles, use the square footage calculator to convert room dimensions to area. If walls above the tile need paint, the paint calculator estimates gallons and coverage. For exterior patios or subfloor fill, the concrete calculator works out cubic yards needed. All calculations run in the browser with no data stored.

Sources

• Angi - Ceramic Tile Installation Cost (2026 Data)
• Homewyse - Cost to Install Ceramic Floor Tile (2026)
• HomeGuide - Tile Installation Cost Guide (2026)
• Tile Council of North America - Handbook for Ceramic, Glass, and Stone Tile Installation
• ANSI A137.1 - Specifications for Ceramic Tile (DCOF slip resistance)
• This Old House - Tile Floor Cost Guide (2026)