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Tile Calculator

Counts the tiles needed for a floor or wall area from the tile dimensions plus the grout joint width, adds a cutting-waste allowance and converts to boxes when the tiles per box are known.

Unit system (optional)Unit system of the length inputs (metric: m / cm / mm; imperial: ft / in). Outputs are reported in both systems. Area to tile (m² or ft²)Floor or wall area to cover, in m² (metric) or ft² (imperial). Tile length (mm or in)Tile length in millimetres (metric) or inches (imperial). Tile width (mm or in)Tile width in millimetres or inches. Grout joint width (mm) (optional)Grout joint width in millimetres for both unit systems (3 mm ≈ 1/8 in; 1.6 mm = 1/16 in is the ANSI minimum). Waste allowance (%) (optional)Extra material for cuts, breakage and offcuts, applied as a multiplier (1 + waste_percent/100). 10 % for straight layouts, 15 % for diagonal patterns or rooms with many cuts. Tiles per box (optional)Number of tiles in one box; optional, enables the box count.

When to use

You need to order ceramic, porcelain or stone tiles for a known area and tile size, including grout joints and waste.

Do not use when: You are laying planks or sheet goods sold by area (use flooring), or need the area itself from room dimensions (use rectangle first).

Formula

footprint = (tile_length + grout_gap) × (tile_width + grout_gap); tiles_no_waste = ceil(area / footprint); tiles = ceil(area / footprint × (1 + waste_percent/100)); boxes = ceil(tiles / tiles_per_box).

Inputs

Parameter	Type	Unit	Required	Description
`unit_system`	enum: metric \| imperial		default metric	Unit system of the length inputs (metric: m / cm / mm; imperial: ft / in). Outputs are reported in both systems.
`area`	number	m² or ft²	yes	Floor or wall area to cover, in m² (metric) or ft² (imperial). Range: > 0, ≤ 100000
`tile_length`	number	mm or in	yes	Tile length in millimetres (metric) or inches (imperial). Range: > 0, ≤ 5000
`tile_width`	number	mm or in	yes	Tile width in millimetres or inches. Range: > 0, ≤ 5000
`grout_gap_mm`	number	mm	default 3	Grout joint width in millimetres for both unit systems (3 mm ≈ 1/8 in; 1.6 mm = 1/16 in is the ANSI minimum). Range: ≥ 0, ≤ 30
`waste_percent`	number	%	default 10	Extra material for cuts, breakage and offcuts, applied as a multiplier (1 + waste_percent/100). 10 % for straight layouts, 15 % for diagonal patterns or rooms with many cuts. Range: ≥ 0, ≤ 50
`tiles_per_box`	integer		no	Number of tiles in one box; optional, enables the box count. Range: ≥ 1, ≤ 1000

Outputs

Output	Type	Unit	Description
`area_m2`	number	m²	Area to tile in square metres.
`area_ft2`	number	ft²	Area to tile in square feet.
`tile_footprint_cm2`	number	cm²	(tile_length + gap) × (tile_width + gap).
`tile_footprint_in2`	number	in²	Same footprint in square inches.
`tiles_needed_no_waste`	integer		ceil(area / tile_footprint).
`tiles_needed`	integer		ceil(area / tile_footprint × (1 + waste_percent/100)).
`boxes_needed`	integer		ceil(tiles_needed / tiles_per_box); only when tiles_per_box is given.

Example

20 m², 300 × 300 mm tiles, 3 mm joints, 10 % waste, 10 per box: {"unit_system":"metric","area":20,"tile_length":300,"tile_width":300,"grout_gap_mm":3,"waste_percent":10,"tiles_per_box":10} → {"area_m2":20,"tile_footprint_cm2":918.09,"tile_footprint_in2":142.3,"tiles_needed_no_waste":218,"tiles_needed":240,"boxes_needed":24}

120 ft², 12 × 24 in tiles, 3 mm joints, 10 % waste, 8 per box: {"unit_system":"imperial","area":120,"tile_length":12,"tile_width":24,"grout_gap_mm":3,"waste_percent":10,"tiles_per_box":8} → {"area_m2":11.15,"tile_footprint_in2":292.27,"tiles_needed_no_waste":60,"tiles_needed":66,"boxes_needed":9}

GET https://tttkmbb.com/api/v1/calculate/tile?unit_system=metric&area=20&tile_length=300&tile_width=300&grout_gap_mm=3&waste_percent=10&tiles_per_box=10

Machine access

API: GET https://tttkmbb.com/api/v1/calculate/tile (query parameters) or POST with a JSON body {"inputs": {...}}
Schema: https://tttkmbb.com/api/v1/calculators/tile · Markdown: https://tttkmbb.com/construction/tile.md · JSON definition: https://tttkmbb.com/construction/tile.json
MCP: server https://tttkmbb.com/mcp, tool run_calculator with calculator_id="tile"
OpenAPI operationId: estimate_tiles_needed
Freshness: static. Authentication: none. Rate limit: fair use (see rate limits).

Sources

FAQ

Why add the grout joint to the tile size?

Each tile occupies its own face plus one joint along each edge, so the effective footprint is (length + gap) × (width + gap); ignoring the joint over-orders by a few percent on small tiles.

How wide should the grout joint be?

ANSI A108.02 requires at least 1/16 in (1.6 mm); 1/8 in (3 mm) is typical for rectified tiles and 3/16 in (5 mm) for calibrated (non-rectified) tiles.

Related calculators

Flooring Calculator — Sheet or plank flooring sold by area.
Rectangle Calculator — Get the area from length and width.