Roofing Calculator
To use this handy roofing calculator, you will need to divide the roof plans into separate rectangular or square areas. Once this is complete, you will need to enter the roof pitch. The roof pitch is measured by dividing the horizontal run by the vertical rise. An easy way to measure the roof pitch (on an existing roof) is to download the Pitch Gauge app on your phone. This lets you rest your phone on the roof and shows you the pitch.
You will then enter the “total length around eaves”, which is basically the total lineal metres around the outer bottom edge. Next, enter the total lineal metres of the hips. Hips are the diagonal lines that measure from the corners of the roof. Finally, enter the total length of the horizontal ridge. Exact measurements are not necessarily required, as you will have a small amount left over at the end to use as spare shingle tiles.
The roofing calculator will calculate the roofing materials required to complete your asphalt shingle roof. I have allowed for waste/offcuts in the roof calculation, including shingles, underlay, and plywood. The 17mm A-Bond C Face / D Face 2400mm x 1200mm Structural plywood is purchased from a local manufacturer, saving on extra costs and freight.