Pro estimator handling hips, valleys, dormers, and multi‑facet footprints with precision today. Enter dimensions, pitch, complexity, openings, valleys, ridges, and materials. Get squares, bundles, rolls, sheets, fasteners, drip edge, starter, and costs in real‑time calculations. Export CSV and PDF to share project summaries easily.
Estimator assumes rectangular main footprint with optional rectangular facets. Verify with drawings and site measurements for irregular geometry.
| Parameter | Example | Units |
|---|---|---|
| Units | Feet | - |
| Footprint length | 40 | ft |
| Footprint width | 30 | ft |
| Eave overhang | 1.0 | ft |
| Rake overhang | 1.0 | ft |
| Pitch (rise/12) | 6 | - |
| Complexity multiplier | 1.05 | - |
| Waste | 10 | % |
| Facet 1 (L×W×pitch) | 12 × 8 × 6 | ft, ft, rise/12 |
| Valleys length | 20 | ft |
| Hips length | 30 | ft |
| Ice & water width | 3 | ft |
| Bundles per square | 3 | bundle/sq |
| Underlayment type | Synthetic | ~1000 sq ft/roll |
| Sheathing sheet | 4x8 | 32 sq ft/sheet |
Use these as starting values. Replace with your project measurements.
| Pitch | Factor | Notes |
|---|---|---|
| 3/12 | 1.031 | Low slope |
| 4/12 | 1.054 | Common Ranch |
| 5/12 | 1.083 | Moderate |
| 6/12 | 1.118 | Steeper working angle |
| 8/12 | 1.201 | Steep |
| 10/12 | 1.305 | Very steep |
| 12/12 | 1.414 | 45° slope |
Factor multiplies plan area to get one-slope surface area before waste.
| Complexity | Suggested Waste | Examples |
|---|---|---|
| Simple | 5–8% | Basic gable, few penetrations |
| Moderate | 8–12% | Gable with dormer, simple hips |
| Complex | 12–18% | Multiple valleys, hips, angles |
| Very complex | 18–25%+ | Cut-heavy architectural roofs |
Adjust waste alongside the complexity multiplier for accuracy.
| Material | Typical Coverage | Estimator rule |
|---|---|---|
| Architectural shingles | 1 square = 100 sq ft | 3 bundles per square |
| #15 felt underlayment | ~400 sq ft / roll | Use rolls = ⌈area/400⌉ |
| #30 felt underlayment | ~200 sq ft / roll | Use rolls = ⌈area/200⌉ |
| Synthetic underlayment | ~1000 sq ft / roll | Use rolls = ⌈area/1000⌉ |
| Ice & water shield | ~225 sq ft / roll | Use eaves length × zone width |
| OSB/Plywood 4×8 | 32 sq ft / sheet | Sheets = ⌈area/32⌉ |
| OSB/Plywood 4×10 | 40 sq ft / sheet | Sheets = ⌈area/40⌉ |
| Ridge cap bundle | ~20 linear ft / bundle | ⌈(hips + ridge)/20⌉ |
Always confirm manufacturer labels for exact coverage before purchasing.
A roofing square equals 100 square feet of roof surface. It’s a buying and estimating unit used for shingles, underlayment, and labor planning. Squares convert directly from total roof area.
Pitch factors come from √(rise² + 12²)/12 and assume a straight, uniform slope. They are accurate for rectangular planes. Complex framing, sags, or tapered runs require field verification and adjustments.
Waste varies with complexity and installer preference. Simple gables may use 5–8%. Moderate roofs use 8–12%. Complex designs may require 12–18% or more. Increase waste for many cuts, valleys, and flashing.
We add ridge and hip lengths, then divide by bundle coverage. Many bundles cover about 20 linear feet. Enter your product’s actual coverage to refine the estimated bundle count.
Yes. Choose meters in the Units menu. The calculator converts lengths and areas to feet and square feet internally so coverage rules and squares remain consistent across systems.
Use the extra facet fields to add rectangular sections with distinct pitch. Increase the complexity multiplier and waste percentage to capture additional cuts, valleys, and fitting around penetrations.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.