You changed the inputs. This is the previous calculation until you select “Calculate boxes” again.
Net surface area
Area including allowance
Total purchased coverage
Coverage above allowance
Estimated equivalent tiles
Coverage used per box
Tiles contained in boxes
Estimated cost
The tile count is a geometric equivalent, not an exact cutting plan. Extra coverage is not necessarily reusable material: cuts, grout joints and layouts matter. Check the carton’s batch, size calibration, shade and stated coverage before buying.
How to calculate tiles and full boxes
This tile calculator estimates material for floors, bathrooms, kitchens and tiled walls. Enter a known area or add non-overlapping rectangular zones, subtract openings and choose an editable allowance for cuts and breakage. When the carton lists area per box, that figure determines the number of boxes. When it lists tiles per box, the estimated coverage comes from the nominal tile dimensions. This is not a tile cutting layout and does not estimate adhesive, grout, trim, waterproofing or suitability for installation.
Example: 20 m² of flooring with 10% extra and 1.44 m² per box → 20 × 1.10 = 22 m²; 22 ÷ 1.44 = 15.28… → 16 full boxes (23.04 m²).
Results are estimates and depend on the supplied values.
Formulas, assumptions and examples
1. Measure the surface
Enter the known area, or add up rectangles without overlaps. Subtract doors, windows and untiled surfaces.
Net area = sum(length × width) − openings.
2. Add a material allowance
The allowance is a planning choice that depends on format, layout, cuts, breakages and any spare tiles. The initial 10% is an editable estimate.
Area with allowance = net area × (1 + allowance / 100).
3. Calculate whole boxes
Use area per box when the manufacturer supplies it. If only pieces per box are given, multiply that count by the nominal area of one tile. Always round up to full boxes.
Boxes = round up(area with allowance / coverage per box).
4. Understand tiles and extra coverage
Equivalent tile count is the area with allowance divided by one nominal tile area. It is not a cutting plan. Extra coverage is the purchased area above the allowance already included.
Equivalent tiles ≈ round up(area with allowance / one tile area).
Scope and limitations
This estimates purchases of one tile product. It does not calculate grout joint spacing, cutting layouts, reuse of offcuts, actual pattern loss, adhesive, grout, trim or installation conditions. Estimate different products separately. Final amounts depend on the packaging and the actual job.
References for method and indicative allowances:
Frequently asked questions about tile quantities
How many boxes of tile do I need for 20 m²?
With a 10% allowance you need to plan for 22 m² of material. If each box covers 1.44 m², 22 ÷ 1.44 = 15.28…, so you would purchase 16 boxes. Check the actual coverage of the product you select.
What percentage of extra tile should I buy?
10% can be a starting point for straightforward layouts, but it is not a universal rule. Diagonal arrangements, numerous corners, large tiles and spare tiles may call for more. Adjust the allowance to your project and your manufacturer’s or installer’s guidance.
Should I use coverage per box or pieces per box?
If the manufacturer prints the covered area per carton, use that value when ordering. If you only know the pieces per box, coverage is estimated from the nominal tile size. Make sure all product details belong to the same tile.
Can I calculate tiles for several bathroom walls?
Yes. Select “Measure zones”, add each wall as a rectangle and subtract untiled doors or windows. Do not double-count overlapping areas. If floor and walls use different tiles, estimate each product separately.
Does this calculator account for grout joints?
It does not model grout-joint width or individual tile placement. Box quantities use the stated box coverage or the nominal area derived from tile count and size, plus your chosen allowance. Check the actual installation layout before ordering.
What does “coverage above allowance” mean?
It is the coverage of full boxes beyond the area already increased by your selected allowance. It is not a guarantee of unused full tiles after installation; actual cuts may produce more or fewer offcuts.
Is the estimated number of individual tiles exact?
No. It is an equivalent count obtained by dividing the planned area by one tile’s nominal area. Actual whole and cut pieces depend on joints, orientation, reuse of offcuts and geometry. Use the carton details for buying boxes.