Tile Adhesive Calculator - Coverage per m2 by Notch Trowel Size
Holds tiles and porcelain.
- 1Dimensions
- 2Result
Material
Tile adhesive
Typical room
What we calculate
Openings (doors and windows)
How many bags of tile adhesive do you actually need? Most people guess, buy too little, then make a second trip. This calculator works differently - it uses your trowel notch size as the primary input, because that single number drives everything. A 4mm notch uses 1.9 kg/m2. An 8mm notch uses 3.5 kg/m2. A 12mm notch uses 6.5 kg/m2. The difference between getting this right and wrong on a 20 m2 bathroom floor is roughly 2-3 extra bags of adhesive.
Colorista.md stocks Ceresit, Baumit, Weber, Knauf, Atlas, and Supraten - all available for delivery across Moldova, including same-day in Chisinau. Enter your area below, pick your trowel, and get a real number.
How Trowel Notch Size Determines Adhesive Consumption
The notch size on your trowel is the single biggest variable in how much adhesive you'll use. Here's the reference table - these are real-world figures, not manufacturer minimums:
| Trowel notch | Adhesive consumption |
|---|---|
| 4 mm | 1.9 kg/m2 |
| 6 mm | 3.0 kg/m2 |
| 8 mm | 3.5 kg/m2 |
| 10 mm | 5.0 kg/m2 |
| 12 mm | 6.5 kg/m2 |
For most standard floor tiles, an 8mm notch is the default - that puts you at 3.5 kg/m2. But for large format tiles (60x120 cm or bigger), you'll need back-buttering as well, which effectively doubles consumption. Same goes for exterior work and underfloor heating systems.
Always add 10% to your calculated total for cuts, waste, and the inevitable spot where your substrate isn't perfectly flat. A bag of adhesive left over costs less than a second delivery.
Which adhesive class do you need?
- C1 - standard adhesive, normal conditions, tiles up to 30x30 cm
- C2 - improved adhesive, better adhesion, recommended for large format
- S1/S2 - flexible adhesive, required for underfloor heating and exterior facades
Step-by-step: Calculating How Many Bags You Need
Walk through this once and you'll never guess again.
Example: 20 m2 bathroom floor, 8mm notch trowel
- Area: 20 m2
- Consumption: 3.5 kg/m2 (8mm notch)
- Total: 20 x 3.5 = 70 kg
- Add 10% waste allowance: 70 + 7 = 77 kg
- Bags needed (25 kg standard): 77 / 25 = 3.1, round up to 4 bags
The 25 kg bag is the standard in Moldova. Some Supraten products come in 5 kg for small jobs.
When to increase your estimate:
- Substrate with visible unevenness (+15-20%)
- Large format tiles requiring back-buttering (multiply by 1.8-2x)
- Exterior applications (+15%)
- Underfloor heating - use S1/S2 flexible adhesive, same consumption rates apply
Why Order From Colorista.md
We carry Ceresit, Baumit, Weber, Knauf, Atlas, and Supraten from our warehouse in Chisinau - not on order, in stock. The calculator above is built on the same consumption figures we use to advise customers every day.
Delivery across all of Moldova. Order online or by phone. If you need help choosing between C1, C2, or flexible S1 adhesive for your specific project - call us, we'll tell you straight.
Frequently asked questions
How much tile adhesive do I need per m2 with an 8mm notch trowel?
With an 8mm notch trowel, adhesive consumption is 3.5 kg per m2. For a 20 m2 area that's 70 kg base, plus 10% allowance = 77 kg total, which means 4 bags of 25 kg. This is the most common scenario for standard floor tiles in Moldova.
How many bags of tile adhesive for 20 square meters?
It depends on your trowel size. With an 8mm notch (the most common): 20 m2 x 3.5 kg/m2 = 70 kg + 10% = 77 kg = 4 bags of 25 kg. With a 10mm notch: 20 x 5.0 = 100 kg + 10% = 110 kg = 5 bags. Always round up.
Do I need to back-butter large format porcelain tiles?
Yes. For tiles 60x60 cm and larger, back-buttering is required - you apply adhesive to both the substrate and the back of the tile. This roughly doubles adhesive consumption compared to the standard trowel-only method. Use C2 or S1 class adhesive for large format work.