Roof Tile Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/6/2026
The number of tiles is calculated by multiplying the roof area by the tile density per square meter for the model chosen, plus a breakage margin. For 100 m² of low-profile interlocking tiles (about 12 tiles/m²) with a 10% margin, you need 1,320 tiles.
Explanation
Unlike concrete blocks, whose density per square meter is standardized, the number of tiles per square meter varies enormously depending on the model chosen: a small flat tile, laid with heavy overlap, needs 65 to 75 per m², while a large low-pitch tile only needs 10 to 12. This calculator offers an indicative average value for each major tile family (low-profile interlocking, standard interlocking, flat, low-pitch): these figures remain useful orders of magnitude for a first estimate, but the actual density of a specific model depends on its exact dimensions and its exposed face (the visible portion of a tile once laid, which determines the overlap with the tile in the next row) — always worth checking on the manufacturer's technical sheet before ordering. A breakage and cutting margin (10% in common use, more for a roof with a complex shape) is added to cover tiles broken during transport or installation, and cuts needed at edges, ridges, and around openings (skylights, chimneys).
Example: 100 m² of roof with low-profile interlocking tiles
Inputs
Area: 100 m². Tile type: low-profile interlocking. Margin: 10%.
Calculation
Number of tiles = 100 × 12 × 1.10 = 1,320.
Result
You need 1,320 tiles for this roof.
Frequently asked questions
Why isn't the roof area the same as the house's floor area?
Because the roof is sloped: its actual surface (the one to cover with tiles) is larger than the floor area it projects onto, more so as the slope gets steeper. You need to use the developed area of the roof slope(s), usually provided by the roof framing plan, not the building's simple footprint.
How do I find the exact density of my tile model?
The manufacturer's technical sheet usually states the number of tiles per m² for the specific model, a more reliable figure than this calculator's indicative average, since it depends on that model's exact dimensions and recommended exposed face (overlap).
Does this calculation include ridge and edge tiles?
No, this calculator only estimates the field tiles (those covering the flat surface of the roof slopes). Ridge tiles, edge tiles, and ventilation accessories are calculated separately, usually per linear meter rather than per square meter.