Do not access a roof for this calculator
Roof work can cause serious injury. Do not climb onto a roof merely to collect inputs. Prefer drawings, ground-level measurements, accessible interior information or dimensions supplied by a competent professional.
RoofFigured does not provide access, ladder, fall-protection or work-positioning instructions. Those decisions require current official guidance, competent planning and appropriate supervision.
Official guidance
United States: OSHA Residential Fall Protection guidance at www.osha.gov/residential-fall-protection/guidance. United Kingdom: HSE Roof work at www.hse.gov.uk/construction/safetytopics/roofwork.htm and HSG33 at www.hse.gov.uk/pubns/priced/hsg33.pdf.
Safety links reviewed 4 September 2026. Consult the authority applicable to the actual location and work.