Roof Tile Calculator
Calculate how many roof tiles you need, based on roof area, tiles per m² and recommended waste.
How to use the roof tile calculator
- Enter the total area of the roof planes to be tiled (add up both roof planes on a gable roof).
- Enter how many tiles the manufacturer specifies per m² for your roof tile type.
- Enter your desired waste percentage for cutting and breakage.
How the number of roof tiles is calculated
The calculator multiplies the area by the number of tiles per m², and adds waste:
For a roof of 120 m² with 10 tiles per m² and 5% waste, that's 120 × 10 × 1.05 = 1,260 roof tiles.
Batten spacing is set by the tile, not by the roof
The number of tiles follows from the area, but the installation follows from which tile you have chosen. Every model has its own recommended batten spacing, which depends on the tile's length and how much overlap the manufacturer requires. Set the battens at the wrong spacing and you get either too little overlap — and with it the risk of wind-driven rain and snow getting in — or a final row that does not meet the ridge.
Roof pitch sets a lower limit as well. Below a certain slope, water does not run off fast enough for the overlap alone to stay watertight, so most tile types have a minimum permitted pitch specified by the manufacturer. On shallow roofs this is normally solved with a more robust underlay rather than with more tiles. This calculator covers the tiles only — battens, underlay, counter-battens and flashings come in addition.
Frequently asked questions
How many roof tiles go on a m²?
It varies by product and tile type. Concrete roof tiles are often around 10 tiles per m², while clay roof tiles often need 12–15 tiles per m² due to their smaller size.
Why does the number of tiles per m² vary between products?
The size of the individual tile, the overlap between tiles, and the roof pitch all affect how many tiles are needed per square meter. Always check the manufacturer's data sheet for the exact figure.
Should I account for waste with roof tiles?
Yes, it's wise to account for some waste for cutting at ridges, edges and penetrations, as well as possible breakage during transport and installation. 5% is a common starting point for simple roofs.