1. Measure the whole room
Record the entire area to tile, including recesses. In the calculator, draw the room or start with a template, then adjust the lengths on the plan. The area updates without splitting the room into rectangles yourself.
Check doors and thresholds too: tiles, adhesive and any preparation must fit within the available height. Keep floor measurements separate from wall measurements.
Draw my room and calculate2. Check the floor before buying adhesive
The base needs to be stable, clean, dry and sufficiently flat. Adhesive cannot replace a floor assessment.
List what needs attention: existing covering, visible defects, level changes, underfloor heating or a wet room. Ask your supplier which product system fits. Levelling compound corrects the floor surface; it is not always needed. Where required, depth and product consumption determine the number of bags.
Estimate levelling compound if needed3. Choose the format and look at the cuts
Straight laying aligns the tiles. Diagonal laying rotates the pattern, usually by 45°. Offset laying staggers the rows; check the permitted offset for your tile. Enter actual tile dimensions and joint width to compare layouts in your room.
Try a few tiles without adhesive to see the edge cuts. The TesCalculs preview shows proportions, but does not choose the best starting point or optimise offcuts. Pay particular attention to doorways and narrow pieces along walls.
4. Turn square metres into boxes
The floor area is your starting requirement. Add an allowance for cuts, possible breakage and any spare tiles you want. A room with many corners or small cuts needs more attention than a simple rectangle: no single percentage is right for every job.
The calculator rounds up to whole tiles, then whole boxes. The budget uses the area actually purchased, not just the floor area. Check the pack label: not every format comes four to a box.
Example: a 20 m² room
A 5 × 4 m room, 60 × 60 cm tiles and four tiles per box. The 10% allowance and €25/m² price are editable examples, not recommendations.
| Item | Calculation / result |
|---|---|
| Floor area | 5 × 4 = 20 m² |
| Area with allowance | 20 × 1.1 = 22 m² |
| One tile | 0.6 × 0.6 = 0.36 m² |
| Tiles before boxing | 22 ÷ 0.36 → 62 |
| Boxes to buy | 62 ÷ 4 → 16 |
| Purchased area | 64 × 0.36 = 23.04 m² |
| Tile cost | 23.04 × €25.00 = €576.00 |
The 64 purchased tiles exceed the 62 needed with this allowance because you buy whole boxes. This cost excludes adhesive, grout, preparation and installation.
5. Count adhesive bags and allow for grout
Single application means adhesive on the base. Back-buttering adds adhesive to the tile back. Follow the manufacturer's method.
Use the consumption specified for your product and installation. Worked example only: 20 m² × 5 kg/m² = 100 kg, or four 25 kg bags before any reserve. Back-buttering does not mean automatically doubling the entered consumption.
For grout, find the consumption for your tile size, thickness and joint width. Multiply it by area and round up to complete packs. The adhesive calculator does not include grout: keep it as a separate item.
Calculate adhesive bags6. Remember the finishing items
Skirting is measured in length, not area. Measure the walls that need it, subtract relevant openings and allow for cuts. If you cut skirting from your floor tiles, add that requirement to the order: the floor allowance does not automatically cover it.
List threshold profiles, spacers, consumables and tools you need. Follow the product's waiting times before grouting or walking on the floor. For outdoors, use the Terrace guide: an outdoor installation needs its own preparation.
Calculate skirting7. Add up the full order
Compare tile prices per m², but cost the complete boxes you will buy. Add floor preparation, adhesive, grout, skirting, delivery and any labour separately. The tile price alone is not the project cost.
Save calculations in My projects to reopen their settings on this device. In another compatible tool, select the same saved zone and enter only missing details, such as adhesive consumption. If the shape changes, check related quantities before ordering.
Open my projectsQuestions before you start
Should I always buy 10% extra tiles?
No. It is an example, not a rule. Tile size, room shape, layout and reusable offcuts change the requirement. Compare the plan with the proposed quantities and choose a suitable reserve.
Can I tile over existing tiles?
Area alone cannot answer that. Have the floor condition and product compatibility checked, including the final height at doors. The calculator estimates quantities, not base suitability.
Why does the box count look high?
It includes your allowance and rounding to complete boxes. Compare purchased area with floor area and check the pack size. Do not add a second allowance to a result that already includes one.
Can I use this guide for a terrace?
It explains quantities, but outdoor bases and installation systems need additional checks. Use the Terrace guide to distinguish bonded tiles from pavers on pedestals.
Check the installation method
These manufacturer resources (in French) provide further guidance. Your product instructions govern use and waiting times.