Tile & Grout Quantity Calculator

How to use

1. Enter your surface size in 'Area (m2)' - measure the finished space, not the room's floor plan.
2. Fill 'Tile length mm' and 'Tile width mm' exactly as printed on the tile box.
3. Set 'Joint mm' to your spacer width and 'Thickness mm' to the tile spec (the 3 mm and 9 mm defaults suit common floor tiles).
4. Enter 'Tiles per box' from the packaging and choose Straight or Diagonal in the layout selector.
5. Read 'Tiles needed', 'Boxes to buy' and 'Grout kg' - boxes always round up to whole packs.
6. Order all boxes from the same production batch where possible, and keep the spares from the waste margin for future repairs.

About this tool

Tile count = area ÷ tile area × 1.10 waste (15% for diagonal layouts). Grout follows the industry formula: kg/m² = (tile length + width) ÷ (length × width) × joint width × tile thickness × 1.6 (all in mm), which accounts for the void volume around each tile edge. Boxes round up to whole packs — buying partial boxes is the classic DIY overspend.

Two formulas decide nearly every tile order: how many tiles cover the floor once waste is allowed for, and how much grout fills the joints between them. This calculator runs both. Tile count is your area divided by one tile's face area, multiplied by a waste factor of 1.10 for straight layouts or 1.15 for diagonals, then rounded up. Grout follows the industry rule of thumb: joint width times tile thickness times a 1.6 packing constant, scaled by tile size, which accounts for the mortar void around every tile edge. Boxes are rounded up to whole packs.

Enter measurements honestly and the outputs land close to what a tiler would quote. Measure the finished area, take tile dimensions from the box rather than memory, and set the joint to what your spacers actually are - 3 mm is a typical floor joint, 2 mm a typical wall joint. The estimate assumes one size of rectangular tile in a simple grid, so herringbone, mosaic sheets and borders need judgment on top. It covers tiles and grout only: adhesive, backer board and trims are separate purchases with their own coverage rules.

FAQ

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