Roof pricing can seem opaque from the outside, but it’s driven by a specific, understandable set of factors rather than being arbitrary.
Square footage is the obvious one, but pitch matters just as much — a steep roof takes longer to work on safely and requires more fall-protection setup than a low-slope roof of the same size. Complexity plays a role too: a roof with multiple valleys, dormers, and penetrations (chimneys, skylights, vents) takes more time and material to flash correctly than a simple rectangular roof.
Material choice is a major lever — basic three-tab shingles, architectural shingles, impact-resistant shingles, and metal roofing all sit at different price points, with tradeoffs in lifespan and durability. Decking condition matters too: if your tear-off reveals rotted plywood that needs replacing, that’s additional material and labor beyond the base estimate, though a good contractor will disclose this as a possibility upfront rather than as a surprise.
The only way to get an accurate number for your specific roof is a real inspection and written estimate — square-footage-based online calculators are a rough starting point at best, since they can’t account for pitch, complexity, or material choice.