📐 Roof Area Calculator – Roofing Square Footage Estimator
Estimate roof surface area in square feet and roofing squares using length, width, pitch, and overhang
Enter your roof dimensions, choose a pitch, and optionally add overhangs, sections, and cost per square. This tool calculates: base area, slope-adjusted roof area, roofing squares, and material cost. Perfect for shingles, underlayment, decking, and estimating labor requirements.
Enter the horizontal distance of the roof section in feet (ridge to eave). Enter the other dimension of the roof section (gable to gable). Pitch factor adjusts the flat footprint for slope. Example: a 6:12 roof has factor ≈ 1.12. Enter the total overhang in inches (both sides). Example: 12 = 1 ft extra length and width. Example: a gable roof has 2 sections (left + right slopes). For L-shaped or complex roofs, enter more. Enter material cost per 100 sq ft (shingles, underlayment, etc.) for budgeting.Result will appear here
💡 Tip: The pitch factor adjusts roof slope to give accurate surface area.
📐 Roof pitch and sizing guidance will appear here after calculation.
✅ Best Practices for Measuring Roof Area:
• Measure each roof section separately, then add totals.
• Always include overhangs — they can add 5–10% area.
• Multiply base area × pitch factor for accurate slope adjustment.
• Double-check dimensions to avoid under-ordering.
• Round up to the nearest square (100 sq ft) for shingle orders.
• Break complex roofs into rectangles/triangles for accuracy.
• Add at least 10% buffer for waste, valleys, hips, and starter strips.
• Consider ridge caps, flashing, vents, and nails for total materials.
• Safety first — steep roofs (>6:12) require harnesses and special care.
❓ FAQ - Roof Area Estimation
Q: What is a roofing square?
1 square = 100 sq ft. Shingles are sold in squares (usually 3 bundles per square).
Q: What is pitch factor?
A multiplier that adjusts flat area for slope. Example: 6:12 ≈ 1.12.
Q: Why add overhang?
Overhangs increase surface area and prevent under-ordering.
Q: How accurate is this tool?
Within 5–10% if inputs are measured correctly. Always confirm on site.
Q: How do I handle irregular roofs?
Break them into simple rectangles and triangles, then sum the results.
Q: What if I don’t know pitch?
Use a pitch app, pitch gauge, or measure rise over run (in inches).
Q: Do steeper roofs cost more?
Yes — more material (higher factor) and more labor/safety requirements.