Tile Adhesive Calculator
Enter the area and the figure your data sheet gives: kg per m² for your trowel notch, or the area one bag covers. The tile adhesive calculator adds your wastage allowance and rounds up to whole bags, in kg or lb.
Tile adhesive calculator
Quantities are estimates. Buy from one batch and keep a few spare pieces for repairs.
In m²; 168 sq ft works too.
Example. Your data sheet gives it for each trowel notch; add back-buttering if you do it.
Typical value. Check your product’s data sheet or box label.
Your price, any currency. Leave blank to skip.
Assumptions
Change any value to match your product or local rules.
Basis: Example allowance for cuts and breakage. Your installer’s figure wins; the Tile Layout Planner counts the cuts for one room.
- Adhesive needed (with wastage)
- 66.5 kg
- 146.7 lb
- Bags
- 4
- Left over
- 13.5 kg
- Cost (your currency)
- Add a price to see the cost
4 bags of 20.0 kg for 15.12 m² with 10.0% added.
How this was calculated
- Adhesive = area × consumption × (1 + wastage); bags = adhesive ÷ bag size, rounded up
- From the bag: bags = area × (1 + wastage) ÷ area one bag covers, rounded up
- Adhesive = 15.12 m² × 4.00 kg/m² × (1 + 10.0%) = 66.5 kg
- Bags = 66.5 kg ÷ 20.0 kg, rounded up = 4
How it works
Enter the area
The floor or wall area you will tile, in m² or sq ft.
Pick your data sheet figure
Consumption in kg per m² for your trowel notch, or the area one bag covers. The defaults are examples.
Enter the bag size
The weight of the bag you buy, in kg or lb.
Read the bags
Adhesive with your wastage allowance, rounded up to whole bags, and what is left over.
Worked example
A 15.12 m² floor with an adhesive that uses 4 kg/m² (an example figure): 15.12 × 4 = 60.48 kg, and 66.53 kg with 10% added. That is four 20 kg bags, 80 kg, with 13.47 kg left over.
In feet: 168 sq ft with a 50 lb bag that covers 90 sq ft. 168 × 1.1 ÷ 90 = 2.05, so you buy 3 bags.
Consumption and the trowel notch
Adhesive data sheets give the consumption for each trowel notch size, in kg per m², or the area a bag covers. A bigger notch leaves a thicker bed and uses more. Your tile size, the flatness of the floor and the product decide the notch. Read the figure for the notch you will use and type it in.
Back-buttering large tiles
Back-buttering means spreading a thin coat on the back of each tile as well as the floor, which many installers do with large tiles. It adds to the consumption. Some data sheets give the extra; if yours does, add it to the kg per m² figure.
Floors and walls
Walls and floors can take different notches, so work them out one at a time and add the bags. Whether one adhesive suits both, and the tile sizes it holds on a wall, is on the product’s data sheet.
Frequently asked questions
How much tile adhesive do I need per m²?
Your data sheet gives it for each trowel notch. Multiply that figure by your area and add a wastage allowance. With an example figure of 4 kg/m², 15.12 m² takes 66.53 kg with 10% added.
How many bags of thinset for 100 sq ft?
Divide the area with wastage by what one bag covers. With an example bag that covers 90 sq ft: 100 × 1.1 ÷ 90 = 1.22, so 2 bags. Use the coverage printed on your bag for your notch.
Does a bigger trowel use more adhesive?
Yes. A bigger notch leaves a thicker bed, so the consumption per m² goes up. Data sheets list a figure for each notch size.
Should I back-butter tiles?
Your tile and adhesive makers and your installer decide. If you do, add the extra adhesive to the consumption figure.
Can I use the same bag for walls and floors?
The product decides. Check its data sheet for where it can be used and the tile sizes it holds.
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