Your roof is bigger than your house footprint, because the slope adds length. This calculator takes your building’s plan dimensions and roof pitch and returns the true sloped roof area, the number that drives every re-roof quote and tile order. Measure the footprint at ground level and you never need to climb up.
Calculate your roof area
Along the ridge, eave to eave.
Across the building, gable to gable.
Most UK pitched roofs sit between 30° and 45°.
How far the roof oversails the wall on each side. 0.3 m is typical.
Geometry only, for budgeting and ordering. It treats the roof as a clean shape and does not deduct for chimneys or dormers, or add for valleys. For a complex roof, treat the result as a close starting point.