TradesHow this works
Enter the roof pitch as rise per 12 inches of run. The tool converts it to degrees and percent slope, gives the sloped-area multiplier you feed into a roofing takeoff, and then answers the field question: is this roof walkable, or does it need roof jacks or staging? It marks which safety tier the pitch falls into.
Treat the walkability call as guidance about footing, not a guarantee. A wet, mossy, or frosted roof is more dangerous than the pitch alone, and working at height is where the serious injuries happen. When in doubt, stay off and hire a roofer.
Common questions
How do I convert roof pitch to degrees?
Take the arctangent of the rise over 12. A 6/12 pitch is arctan(6/12), which is 26.6 degrees. A 12/12 pitch is a perfect 45 degrees. This tool does the conversion and also gives the percent slope and the sloped-area multiplier.
What is the roof area multiplier?
It is how much bigger the actual sloped roof is than its flat footprint. The formula is the square root of rise squared plus 12 squared, all over 12. A 6/12 roof has a multiplier of about 1.118, so multiply the footprint area by 1.118 to get the real roof surface for a shingle takeoff.
What pitch is walkable?
As a rule of thumb, roofs up to about 6/12 are walkable with soft-soled shoes and care on a dry day. From 7/12 to 9/12 is steep enough to want roof jacks and fall protection. At 10/12 and above, plan on staging or a harness, or hand it to a roofer.
Is a low-slope roof always safe to walk?
No. Conditions beat pitch. A gentle roof that is wet, mossy, frosted, or made of brittle or slick material can be more dangerous than a dry steep one. Read the surface, not just the number, and never treat a walkability tier as a guarantee.
What counts as a steep-slope roof?
Roofing materials generally call anything over 4/12 steep-slope, which affects underlayment and installation. That is a materials term, separate from walkability. For footing and safety, most people can move on a dry roof up to about 6/12 before it gets genuinely hazardous.
Sources: Exact trig: degrees = atan(rise/12); percent = rise/12 x 100; area multiplier = sqrt(rise^2 + 12^2)/12 · Walkability tiers (footing guidance, not code): ~6/12 walkable, 7-9/12 roof jacks + fall protection, 10/12+ staging/harness/pro. Engine version 1.0.0. Risk tier 1.