About My Roof Pitch
My Roof Pitch publishes free roofing and framing calculators that show the full working behind every number. Each tool is built from published formulas and code minimums, reviewed against worked examples, and covered by automated tests that run on every change.
Why we show the working
Most roofing calculators return a number and nothing else. Ours print the intermediate steps — the ratio, the arctangent, the multiplier — so you can check the result against a framing square, a bid, or a plan set before you order material.
Sources we rely on
- 2021 International Residential Code, Chapter 9, for minimum slopes by material.
- ASCE 7 for snow and wind load methods.
- International Plumbing Code for roof drainage slope minimums.
- Manufacturer installation instructions where they are stricter than code.
Limits
Every result is a planning estimate. Structural, code and permit decisions belong to a licensed engineer or your local building department. If a result looks wrong, tell us the inputs you used and we will re-check the formula.