Roof geometry, worked out properly
Roofing numbers come from triangles, not from rules of thumb. Each calculator takes the real measurements — footprint, pitch, overhang — and returns sloped area, material counts and the framing lengths behind them. Every formula is on the page, and every table is recomputed on each build.
Calculators
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Hip roof
Hip roof calculator
Sloped area, squares, bundles, ridge length, all four hip lines and the eave perimeter — from footprint, pitch and overhang.
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Shingles
Shingle bundle calculator
Plan area, pitch and waste in, whole bundles out — including the slope step that the "divide by 33.3" shortcut leaves out.
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A roof is a set of planes over a plan. Once you know the plan dimensions and one pitch, the sloped area, the ridge, the hips and the rafter lengths are all determined — there is nothing to guess. The hard part in practice is measuring the plan correctly and knowing which length you are being asked for. That is what these pages are for.
They are deliberately small tools. One question, several inputs, a result you can check by hand against the formula printed underneath it.
What is coming next
Gable, shed and pyramid roofs are the next three shapes, followed by roof pitch and rafter length, then truss counts and metal panel takeoffs. They will appear here as they are finished and checked, not before — a calculator with an unverified table is worse than no calculator.
Why the formulas are on the page
Any roof calculator can print a number. Printing the multiplier, the right triangle it came from and a table you can recompute with a phone calculator is what lets you decide whether to trust it on your own roof. The method page explains how each table is verified before publication.