Tile Grout & Adhesive Calculator
Grout and tile adhesive in kg and bags, from tile size, joints and the product data sheet.
Tiled areas
Grout
Tile adhesive
Prices optional
Each area
| # | Tile and joint | Grout per m² | Grout |
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About the Tile Grout & Adhesive Calculator
Work out how much grout and tile adhesive to buy for a floor, a shower or a kitchen splashback. Enter each tiled area with its tile size, joint width and joint depth, and the calculator applies the joint-volume formula that grout manufacturers print in their technical data sheets — kg per m² = (L + W) ÷ (L × W) × joint width × joint depth × the grout's coverage figure — to give the grout in kg and bags.
Tile adhesive comes from the figure on the adhesive's data sheet: kg per m² per mm of bed, the kg per m² for your trowel notch, or the area one bag covers. Several areas with different tiles can be added together, and prices give the cost.
How to use it
- Choose Metric or US units. For each tiled area enter the area, the tile size (for hexagons, the size across the flats), the joint width and the joint depth — usually the tile thickness.
- Pick the grout. Its coverage figure comes from the data sheet named under it; for another product type its own figure. Set the bag size and an extra for mixing and cleaning losses.
- For tile adhesive choose how its data sheet gives the consumption — per mm of bed, per m² for your trowel, or the area per bag — and the bag size.
- Add prices per bag for the cost, then copy the result or download the table as CSV.
Examples
(150 + 150) ÷ (150 × 150) × 5 × 5 × 1.75 = 0.58 kg/m² — a 10 kg bag grouts about 17 m² (the ARDEX-FLEX FL data-sheet example)
300 ÷ 22,500 × 3 × 5 × 1.5 = 0.30 kg/m² — about 33 m² per 10 kg (the ARDEX-FLEX FS example)
0.175 kg/m² × 12 m² = 2.1 kg of grout
4.2 kg/m² × 28 m² = 117.6 kg + 10% = 129.4 kg → 7 bags of 20 kg
The grout formula
Grout data sheets give the same calculation, with all sizes in millimetres: add the tile's length and width, multiply by the joint width, the joint depth and the grout's coverage figure, then divide by the length and by the width — the answer is kg of grout per m² (ARDEX-FLEX FL technical data sheet).
(L + W) ÷ (L × W) is the length of joint in each square metre: every tile in the grid owns one long and one short joint. Small tiles have far more joint per m² than large ones, so mosaics take many times more grout. For hexagons measured across the flats F the joint length per area is 2 ÷ F — the same as a square of side F. Because the formula divides by the tile's own area rather than the tile plus its joint, it slightly overstates the grout — a small margin in your favour.
Coverage figures from data sheets
The coverage figure is the kg of grout powder that fills one litre of joint, and it differs between products, so use your grout's own figure when it gives one. The presets come from these data sheets:
- 1.75 — ARDEX-FLEX FL, a cement-based grout for joints 3–15 mm
- 1.5 — ARDEX-FLEX FS, a cement-based grout for joints up to 4 mm
- 1.5 — ARDEX EG 18 PLUS, an epoxy grout for joints 2–12 mm
Tile adhesive
Adhesive data sheets state the powder needed per m² per mm of bed, or a coverage for a trowel notch size. Two examples: ARDEX X 7 R needs about 1.4 kg of powder per m² per mm, so a 20 kg bag covers about 4.7 m² at a 3 mm bed (data sheet); lightweight ARDEX X 77 needs about 1.05 kg per m² per mm, and a 20 kg bag covers up to 8 m² with an 8 × 8 mm square-notched trowel (data sheet).
The bed thickness is what remains after the tiles are pressed in, not the notch depth. Large tiles, uneven backs and back-buttering need more, so a figure from your own product and trowel is better than a general one.
Limitations
- The formula assumes square or rectangular tiles in a grid (or regular hexagons); for other shapes and patterns it is an approximation.
- Joints are taken as filled to the depth you enter; adhesive squeezed into joints, rounded tile edges and textured surfaces change the real amount.
- Coverage figures and adhesive consumption vary between products — the presets are the named products' published figures, not a rule for every grout.
- Pricing is per bag only; the calculator does not know your supplier's pack sizes beyond the size you enter.
Privacy
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.
Frequently asked questions
How much grout do I need per square metre?
It depends mostly on the tile size: (L + W) ÷ (L × W) × joint width × depth × coverage figure, all in mm. 600 × 600 × 10 mm tiles with 3 mm joints need about 0.18 kg/m² at a figure of 1.75; 150 × 150 × 5 mm tiles with 5 mm joints need 0.58 kg/m²; 25 × 25 mm mosaics with 2 mm joints 4 mm deep need about 1 kg/m² at a figure of 1.5.
What is the grout coverage figure?
It is the grout's density in kg of powder per litre of joint, the number manufacturers print for this formula. ARDEX gives 1.75 for its FLEX FL grout and 1.5 for FLEX FS and the EG 18 PLUS epoxy grout. If your product's data sheet gives one, enter it.
How deep is the grout joint?
Usually the full thickness of the tile — the data-sheet examples use the tile thickness as the joint depth. If adhesive fills the bottom of the joints, enter the depth that will really be grouted.
How much tile adhesive do I need?
Multiply the bed thickness by the data sheet's kg per m² per mm (about 1.4 for a standard cement adhesive such as ARDEX X 7 R): a 3 mm bed needs about 4.2 kg/m². Or use the coverage the data sheet gives for your trowel notch.
Does it work for hexagon or mosaic tiles?
Yes. Choose Hexagon and enter the size across the flats; for mosaics enter the size of one small tile, not of the sheet. Mosaics use much more grout per m² because they have so much more joint.