Estimate tile adhesive from product coverage
Adhesive consumption varies with tile, trowel and substrate. Enter the selected product’s kg/m² rate or m² per bag, then plan the whole bags to purchase.
Back to calculator ↑Find the net installation area
Measure the surface in metres and subtract areas that will not receive tile. Alternatively enter the known net area. For several walls, add only the sections that will use the same adhesive. Different substrates or tile systems may call for separate calculations.
Inspect the existing surface and the adhesive instructions before ordering. Bed thickness, trowel notch and back-buttering can change actual usage. A bag estimate cannot establish that a substrate is sound, clean or ready for tile.
Read the bag coverage correctly
If the technical sheet gives kg/m², enter that directly. If it gives m² per bag, enter both coverage and bag weight; the calculator converts the rate as bag kg ÷ m² per bag. For example, a 20 kg bag covering 4 m² implies 5 kg/m². TOA Silvertile publishes that illustrative coverage, but another product may differ.
The engine multiplies net area by the chosen kg/m² rate, applies your allowance once, divides by bag size and rounds up. Use the allowance to reflect reasonable site loss; do not add it again to the final number of bags.
Worked example for 20 m²
A 20 m² floor at 5 kg/m² needs 100 kg before allowance. Add 10% once to get 110 kg. With 20 kg bags, ceil(110 ÷ 20) gives six bags, or 120 kg purchased. The 10 kg difference is a mathematical buffer, not a promise of usable leftovers on site.
At an illustrative ฿180 per bag, six bags cost ฿1,080. That figure excludes surface levelling, tiles, grout, labour and delivery. Confirm the selected bag’s weight before using a price from a listing.
Match adhesive to the job
Check the adhesive’s stated suitability for tile type and size, substrate, floor versus wall, wet area and interior versus exterior use. Similar bag weights do not make products interchangeable. Verify working time, mixing water and curing instructions for the exact product.
Ask the installer to review the product rate against the actual trowel and bedding method, especially for large tiles or uneven surfaces. Record the exact SKU and batch for any top-up purchase. The calculator estimates quantity; it does not approve a material specification.
Common questions
Does 4 m² per bag apply to every adhesive?
No. It is one product’s example; use the chosen product’s own technical rate.
Should I add extra bags after the allowance?
The engine applies allowance before rounding to bags, so avoid accidentally counting it twice.
Does this include grout?
No. Grout depends on tile and joint geometry and needs a separate estimate.
Sources and calculation guidance
Check these against your chosen product’s label and instructions.