Example 1
- Area: 18 m²
- Consumption: 3.5 kg/m²
- Waste: 10%
- Bag size: 25 kg
You need 69.30 kg of adhesive
That equals 3 full bags
This is a typical case where bag count matters more for purchasing than the kilogram value alone.
Tile adhesive requirement calculator
Type area in m² and coverage from the bag or the trowel notch. The calculator multiplies area by kg/m², adds waste, and rounds bags up. An 18 m² room at 3.5 kg/m² and 10% is 69.30 kg, three 25 kg bags. A 7.2 m² bath at 4.0 kg/m² and 8% is 31.10 kg, two 20 kg bags.
Shopping estimate: kg from area and coverage (or trowel notch), plus waste, then full bags. Need square footage or a tile count first? Try floor area or tile quantity, then come back for adhesive.
Results
Area (m²), Consumption (kg/m²), Waste / spare (%) and Bag size (kg). The result shows up here.
How the results are calculated
Tile adhesive requirement counts kilograms and bags. The formula is area times consumption times a type factor times (1 plus waste), and bags are ceil(kg divided by bag size). Bed thickness in mm converts to consumption at about 1.5 kg/m² per millimeter when you use a trowel notch instead of the bag label.
An 18 m² living room at 3.5 kg/m² and 10% waste is 69.30 kg. With a 25 kg bag that is 3 full bags, because 69.30 / 25 rounds up. A 7.2 m² bath at 4.0 kg/m² and 8% is 31.10 kg, two 20 kg bags. A large format on 24 m² at 5.2 kg/m² and 12% is 139.78 kg, six 25 kg bags.
Type area in m² and consumption in kg/m² from the bag. Waste, bag size, bed thickness, trowel notch, adhesive type, and price are optional. If you type thickness in mm instead of consumption, the calculator uses about 1.5 kg/m² per mm. A comma and a period are the same number.
Tile piece count lives on the tile calculator: 18 m² at 60×60 cm and 10% is 56 tiles, and adhesive still follows area, not piece count. Raw 5 by 4 m is on floor area and gives 20 m² to paste back here.
Bags round up. 2.1 bags means three, not two, because leftover on the trowel and an uneven floor eat the spare. A 3 mm thin bed and a 10 mm notch are two different coverages; take one number from the bag or the notch, not both at once.
Type 18 and 3.5, set 10% and a 25 kg bag, click Calculate, and match 69.30 kg and 3 bags. Then 7.2 and 4.0 at 8% and 20 kg: 31.10 kg and 2 bags.
How to use this calculator
- Type area in m², for example 18 for a living room or 7.2 for a bath.
- Enter consumption in kg/m² from the bag, or pick a trowel notch. Thickness in mm is the alternative, about 1.5 kg/m² per mm.
- Set waste, usually 8-12%, and bag size, for example 25 kg.
- Click Calculate. 18 m², 3.5 kg/m², and 10% give 69.30 kg, which is 3 bags of 25 kg.
- Tile pieces belong on the tile calculator. This page stays with kilograms of adhesive.
Adhesive at 3.5 kg/m² on 18 m²
Area times coverage plus waste, bags rounded up. An 18 m² room at 3.5 kg/m² and 10% is 69.30 kg, three 25 kg bags.
- kg/m²
- Coverage from the bag or the trowel notch. 3.5 on 18 m² plus 10% is 69.30 kg. A 7.2 m² bath at 4.0 and 8% is 31.10 kg.
- m²
- Tiled area to bed. 18 m² at 3.5 kg/m² is those three 25 kg bags, not a 60×60 piece count.
Example scenarios
Example 2
- Area: 7.2 m²
- Consumption: 4.0 kg/m²
- Waste: 8%
- Bag size: 20 kg
You need 31.10 kg of adhesive
That equals 2 full bags
Even on smaller areas, reserve still matters because some material is always lost during mixing, spreading, and touch-ups.
Example 3
- Area: 24 m²
- Consumption: 5.2 kg/m²
- Waste: 12%
- Bag size: 25 kg
You need 139.78 kg of adhesive
That equals 6 full bags
With larger tile formats or a thicker adhesive layer, the total rises quickly, which is why it is better to calculate it early instead of guessing.
Related calculators
FAQ
How much adhesive for 18 m² at 3.5 kg/m² and 10% waste?
69.30 kg. With a 25 kg bag that is 3 full bags, because 69.30 / 25 rounds up.
How many bags for 7.2 m² at 4.0 kg/m², 8%, and a 20 kg bag?
31.10 kg, which is 2 bags. A small bath with a thicker notch uses more kilograms per meter.
How many bags for 24 m² at 5.2 kg/m² and 12%?
139.78 kg. At 25 kg that is 6 full bags after rounding up.
How does thickness in mm become consumption?
About 1.5 kg/m² per millimeter when you use bed thickness instead of the label. 4 mm is on the order of 6 kg/m² before waste.
What waste should I add for adhesive?
Usually 8-12%. An uneven floor and a large format sit near the top. Bags still round up.
Does tile count multiply the adhesive?
No. The inputs are area and kg/m². 56 tiles from an 18 m² room do not change 69.30 kg while the area stays 18.
Where do I get area if I do not have 18 m²?
On floor area: 5 by 4 m is 20 m². For walls, deduct openings on the wall area page.
Can I buy 2 bags when the result is 2.1?
Round up. Leftover on the trowel and an uneven floor eat a fraction of a bag.
Should I type trowel notch and bag coverage together?
Pick one source. A notch preset fills kg/m². Two different entries break the scale.
How much adhesive for 20 m² at 3.5 kg/m² and 10%?
77 kg before bags. At 25 kg that is 4 bags, because 77 / 25 = 3.08, rounded up to 4.
Knowledge sources
Volume and waste come from the sizes you type. Below are volume and NIST SI units.
Page updated in 2026.