Rafter Roof Calculator

Rafter Roof Calculator is a job-site tool for carpenters, framers, contractors, and serious DIYers who need accurate rafter and birdsmouth layout in imperial feet-inches-fractions.

• Full rafter geometry: total length, top length, rise, run, fall, setback, and tail/overhang along the rafter • Birdsmouth layout: plumb depth or seat width modes, plus a safety warning when the notch is too deep • Height Above Plate (HAP): instantly see remaining rafter depth over the wall plate • Pitch & angle input: quick common pitch selector plus degree entry for custom roofs • Secondary helper: calculate rafter run from building width and ridge thickness, then “Use This Value” in the main screen • Interactive diagrams: scroll/pan views with grid and scale for the full rafter profile and a close-up birdsmouth detail • PDF export: save/share a clean report with inputs, results, timestamp, and warnings

Built for speed and reliability: real-time updates (no Calculate button), offline operation, and privacy-friendly (no tracking).