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Tiles & flooring

Grout calculator

Estimate grout from product coverage or joint geometry, rounded to whole packs. See clear formulas, worked examples, assumptions and a printable estimate.

Grout Calculator

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Product & method

Use one grout product, color and complete pack size across all areas. Starting coverage, pack mass, allowance and price are examples, not verified product data.

Take K from the manufacturer’s formula using millimeter tile/joint dimensions and kg/m² consumption. K is product-specific and stays unchanged when switching to US units. Do not substitute loose powder density or assume a universal cement/epoxy factor.

Tiled areas & joints

Use actual installed area, including its joints, without a tile-purchase waste allowance. Filled joint depth is the depth receiving grout, not automatically the full tile thickness. Geometry mode approximates uniform rectangular tiles and joints; movement and perimeter joints are excluded.

Pack cost

For multi-component products, one pack means a complete kit. No partial-kit mixing is planned. Currency changes its label only; no exchange-rate conversion. Labor, tax and delivery are excluded.

How to useCalculation methodRead the project guide

How to use

  1. Choose product coverage when a suitable manufacturer coverage figure is available. Enter the area covered by one pack for your tile and joint conditions.
  2. Alternatively choose Joint geometry and supply tile dimensions, joint width, filled joint depth and the product coefficient.
  3. Add zones using the same grout product, then enter pack mass, allowance and pack price.
  4. Review mass before allowance, required mass and whole-pack purchase mass separately.

Calculation method

Product coverage uses rate = pack mass / covered area per pack. Joint geometry uses rate in kg/m² = (A + B) / (A × B) × W × D × K, where tile sides A and B, joint width W and filled depth D are in millimetres and K is the product coefficient. Zone mass equals rate × area × quantity. Sum the zones, apply the allowance and round required mass up to whole packs.

Worked example

For 12 m², a 2 kg pack covering 10 m² gives 2.4 kg before allowance and 2.64 kg with 10% extra. Buy 2 packs, totaling 4 kg; at 20 USD per pack the cost is 40 USD. In geometry mode, 300 × 300 mm tiles, 3 mm joints, 8 mm filled depth and K = 1.6 give 0.256 kg/m², or 3.072 kg before allowance for 12 m².

Assumptions and limits

Geometry is an approximation for a regular joint grid; joint width must be smaller than both tile sides. The coefficient is product-specific and deliberately has no starting value. Filled depth can differ from tile thickness. Irregular tiles, mosaics, profiles and installation losses can need a different model. Do not use a generic coefficient as manufacturer data.

Units, prices and saved estimates

Physical values are stored internally in metres, square metres, cubic metres or kilograms as appropriate. Changing measurement units converts their display; choosing a currency changes its label without applying an exchange rate. Purchase quantities use unrounded calculations. Money is shown to two decimal places.

Edits can be saved in this tab. Optional device saving lasts seven days after the last save. Copy, TXT download and a separate printable report use the current valid estimate. Delete draft removes saved inputs without resetting the visible form. The privacy choices page can remove all calculator drafts.

For practical measurement decisions, read choosing grout coverage and checking joints.