HammerCalc’s rafter calculator helps roof carpenters and framers work pitch, common rafters and hip math with interactive diagrams — inside the same construction calculator you use for everyday feet-and-inches work.
Use visual sliders and diagrams to work through roof pitch and rafter lengths instead of hunting through lookup tables. HammerCalc pairs rafter tools with a modern keypad so layout and cut math stay in one app.
Legacy construction calculators bury roof tools in dense key sequences. HammerCalc puts the rafter calculator and roof tools behind clear visuals — without giving up pro-grade dimensional math.
For a common rafter: rise = run × (pitch_in_12 / 12), then rafter_length = √(run² + rise²). Roof angle ≈ arctan(rise / run). This is the same math behind a roof pitch calculator and roofing calculator workflow.
Length = √(run² + rise²) · 12 ft run @ 6/12 → √(12² + 6²) ≈ 13 ft 5 in
A framing check before you mark the birdsmouth:
Yes. HammerCalc includes interactive rafter and roof tools with diagrams for job-site framing math.
Yes. Work pitch and related rafter values visually inside the same app.
Multiply the run by pitch/12 to get rise, then take the square root of run² + rise². HammerCalc’s rafter and roof tools do this with live diagrams.
Pitch tools focus on slope (rise over 12) and angle; rafter tools turn that pitch plus span/run into cut lengths. HammerCalc includes both in the same framing workflow.
Stairs, square footage, feet & inches, metric & imperial — all in HammerCalc.
