床や壁に必要なタイル・箱数を計算。ストレート貼り、斜め貼り、ヘリンボーンなど張り方によるロス率と、目地部分の面積も考慮。
| 項目 | 値 |
|---|
タイルの必要枚数: 有効タイルサイズ=(タイル縦+目地幅)×(タイル横+目地幅)。必要枚数=面積÷有効サイズを切り上げ。
張り方によるロス率: 芋張りは10%、レンガ張り(ずらし張り)は12%、斜め張りは15%、ヘリンボーンは20%—端部のカットや回転によって使えない端材が増えるため、その分多めのタイルが必要になります。
目地の面積: 全体の面積から(タイル枚数×タイル縦×タイル横)を差し引いた値—目地材の必要量の見積もりに役立ちます。
箱数: 必要枚数÷1箱あたりの枚数を切り上げて、箱単位で購入する数を求めます。
The tile count is an area division done in millimetres. Your tile size is padded by one grout gap on each axis, giving an effective footprint of (tile length + gap) × (tile width + gap); the floor area is divided by that footprint and rounded up to get the bare tile count. The pattern waste percentage is then applied on top and rounded up again. Grout area is reported separately as floor area minus the bare tiles multiplied by their unpadded size.
Pattern choice is the main waste driver: Straight adds 10 percent, Brick / offset 12 percent, Diagonal 15 percent and Herringbone 20 percent, because rotated and staggered layouts throw away more of each cut tile. Tiles per box, default 10, converts the tile count into boxes to buy. Note that the grout gap is entered in millimetres in both unit systems, even when tile dimensions are in inches — 3 mm is the default and a common wall and floor spacing.
This is area maths, not a layout. It never works out which rows fall where, so it cannot tell you that a room whose width leaves a two-inch sliver at one wall will burn far more tile than the flat percentage suggests. Columns, islands, hearths and door reveals are not deducted. The grout figure is an area, not a volume, because joint depth is not an input, so treat it as a rough guide when buying grout by the bag.
About 130. The 120 square foot floor divided by a 12 inch tile padded to 307.8 mm by a 3 mm grout gap gives 118 bare tiles, and the straight-pattern 10 percent waste takes it to 130, which is 13 boxes at 10 per box.
Select Herringbone and the tool adds 20 percent, double the 10 percent it uses for a straight lay. Herringbone cuts every perimeter tile at 45 degrees and rarely leaves a usable offcut, which is why it carries the highest waste factor of the four patterns.
Yes, more than people expect. A 3 mm joint turns a 304.8 mm tile into a 307.8 mm footprint, roughly two percent more area each. Across a whole floor that is a tile or two, and on small mosaic tiles with wide joints the effect is much larger.
Yes. Switch Area input to Direct area and type the square footage or square metres you measured, instead of a length and width. That is the right mode for anything that is not a plain rectangle, such as an L-shaped floor or a run of splashback.
It is the floor area left uncovered by the bare tile faces, so it scales with how much joint you are filling. Use it to compare joint widths or to sanity-check a grout bag's coverage claim, but remember it has no depth term and is not a volume.
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