Construction calculator
Roofing Calculator
Estimate roofing materials based on roof area and pitch.
How the calculation works
Multiply flat area by the pitch factor: factor = √(1 + (pitch÷12)²). A 6:12 pitch has factor of 1.118.
Example: A 20 × 30 ft roof with 6:12 pitch needs 672 ft² of shingles.
Important limitations
This tool provides a mathematical estimate based only on the values entered. It does not account for regulations, taxes, lender fees, medical circumstances, structural requirements, or other project-specific factors unless explicitly stated.
Frequently asked questions
How accurate is the roofing calculator?+
The calculation follows the displayed formula and retains full numeric precision before formatting the result.
Can I use the result professionally?+
Use it as a planning estimate. Confirm regulated, medical, financial, or construction decisions with a qualified professional.