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Tile, Grout and Adhesive Calculator

Enter the area, the tile size and the joint width and depth. The calculator counts tiles with a waste allowance, works out the grout volume and, if you enter figures from the bags, the weight of grout and adhesive. 10 m² of 300 × 300 mm tiles with 3 mm joints 8 mm deep needs 1.6 litres of grout before waste.

Measurements

Units

Usually the tile thickness.

Optional: kg per litre of mixed grout, to estimate the weight to buy.

Optional: kg per m² for your trowel size, as printed on the adhesive.

Results

Tiles

108 pcs

Grout volume

1.69 L

Show the working
  1. Tiles⌈100 ft² ÷ ((12 in + 0.13 in) × (12 in + 0.13 in)) × (1 + 10%)⌉ = 108
  2. Grout volume100 ft² × (L + W) ÷ (L × W) × 0.13 in × 0.31 in × (1 + 10%) = 1.69 L

Material takeoff

ItemQuantityUnit priceCost
Tiles108 pcs–
Grout2 L–
Estimated total–

Enter your local prices to estimate the cost. Prices aren't stored anywhere.

Paper and orientation
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How to use the tile and grout calculator

  1. Choose Metric or Imperial.
  2. Enter the area to tile.
  3. Enter the tile length and width, the joint width and the joint depth (usually the tile thickness).
  4. Optionally enter the grout density and adhesive consumption from the bags.
  5. Set a waste allowance and price the takeoff.

How the calculation works

Tiles = area ÷ ((length + joint) × (width + joint)) × (1 + waste), rounded up. Grout volume = area × (L + W) ÷ (L × W) × joint width × joint depth × (1 + waste). Grout weight = volume × density. Adhesive = area × consumption × (1 + waste).

Worked examples

Bathroom floor. 10 m² of 300 × 300 mm tiles, 3 mm joints, 8 mm deep, no waste: 109 tiles and 1.6 litres of grout.

Mosaic splashback. Small tiles have many more joints. 2 m² of 50 × 50 mm mosaic with 2 mm joints 6 mm deep: 2 × (0.1 ÷ 0.0025) × 0.002 × 0.006 = 0.96 litres, about three times as much per m² as the bathroom floor.

How to interpret the results

Grout is sold by weight. Use the bag’s density to convert, and round up to whole bags. Mixed grout has a limited working time, so mix only what you can use.

Tips and common mistakes

  • Measure joint depth, not just width; deep joints use much more grout.
  • Order tiles from one batch; colours vary between batches.
  • Plan the layout before buying; centring the pattern changes the number of cuts.
  • Follow the adhesive trowel size recommended for your tile size.

Choosing joint width

The joint width affects both the look and the grout quantity. Wider joints hide small size differences between tiles, while narrow joints give a cleaner look but need tiles with very consistent sizes. Follow the tile and grout manufacturers’ recommendations: some grouts are made for narrow joints and others for wide ones. Doubling the joint width doubles the grout volume, as the formula shows, so check your choice before buying.

Measure rooms with the square footage calculator, plan the whole renovation budget with the renovation cost calculator, and send the tiles, grout and adhesive to your project materials list. For walls that need boarding before tiling, the drywall calculator estimates the sheets and fixings.

Assumptions and limitations

The formula assumes a regular grid of rectangular tiles. Hexagons, herringbone and other patterns have different joint lengths.

Frequently asked questions

How do I calculate grout?

Grout volume = area × (tile length + tile width) ÷ (tile length × tile width) × joint width × joint depth. The first part is the length of joint per square metre.

How much grout do I need per square metre?

For 300 × 300 mm tiles with 3 mm joints 8 mm deep, about 0.16 litres per m². Smaller tiles and wider joints need much more.

How do I convert litres of grout to kilograms?

Multiply by the density of mixed grout printed on the bag (kg per litre). Enter it in the calculator to see the weight to buy.

How much tile adhesive do I need?

Adhesive consumption depends on the trowel notch and the tile. The bag gives kg per m² for each trowel size; enter it to get the total.

How many spare tiles should I buy?

Add 10% for cuts and breakage in simple rooms, more for diagonal layouts or large-format tiles. Keep a few spare tiles from the same batch for future repairs.

Sources