Roofing Shingles Calculator
The Roofing Shingles calculator shows the roof squares, bundle count, nails, and underlayment rolls you’ll need—factoring in pitch and waste for ridges/valleys.
We let you enter either a known roof area or a building footprint (length × width) with pitch to estimate total roof area. Add a waste percentage for cuts and features, choose coverage per bundle, and we’ll return a clean materials list. Use it for quick takeoffs and to sanity-check quotes; if you prefer manual math, see the formulas below.
Enter a known roof area or use length × width with pitch. Add a waste percentage for ridges, hips, valleys, and offcuts. Pick bundle coverage and underlayment type; we’ll compute squares, bundles, nails, and rolls.
For simple footprints, multiply L×W and apply the pitch multiplier.
Multiplier ≈ √(1 + (rise/12)²). Steeper roofs need more shingles.
Typical 7–15% (more with lots of hips/valleys).
Common: ~33.3 ft²/bundle (≈3 bundles per square).
Local code may require 6 nails in high-wind zones.
These are planning estimates. Include ridge/hip/shingle type requirements and local code before final ordering.
Results interpretation
How it works
We convert your footprint and pitch into sloped roof area, add waste, and divide by standard coverage units.
Formulas, assumptions, limitations
Pitch multiplier. √(1 + (rise/12)²) applied to horizontal area L×W to estimate sloped area.
Waste. Cut loss at valleys, hips, rakes, ridges, and penetrations. Typical 7–15%; steep/complex roofs can exceed 20%.
Squares → bundles. 1 square = 100 ft². Bundles ≈ ceil(Area_with_waste ÷ BundleCoverage).
Nails. Shingles/square ≈ 79. Nails ≈ squares × shingles/square × nails/shingle (4 or 6).
Underlayment. Rolls ≈ ceil(Area_with_waste ÷ EffectiveRollCoverage).
Use cases & examples
Footprint 2000 ft²; multiplier ~1.118 → ~2236 ft²; with waste → ~2460 ft². Squares ≈ 24.6; bundles (33.3) ≈ 74; nails (4/shingle) ≈ ~24.6×79×4 ≈ 7770; 15# felt → ceil(2460/432) = 6 rolls.
Area with waste → 3584 ft²; squares 35.84; bundles (33.3) → ceil(107.6) = 108; nails (6/shingle) → ~35.84×79×6 ≈ 17,0xx.
Footprint 120 ft²; multiplier ~1.031 → 124 ft²; with waste 134 ft²; ~1.34 squares; bundles (33.3) → 5; nails (4/shingle) → ~424.
Roofing shingles FAQs
What is a roofing square?
A square is 100 square feet of roof coverage.
How many bundles per square?
Typically ~3 bundles per square (each bundle ~33.3 ft²), but check your product wrapper.
How much waste should we allow?
Many roofs use 7–15%. Add more for hips/valleys, dormers, complex geometry, and pattern matching.
Does pitch change material needs?
Yes—steeper roofs have more surface area than the footprint; we use a pitch multiplier from rise/12.
Are nails estimated accurately?
They’re planning numbers. Local code and manufacturer specs govern nail count and placement.
What about ridge caps and starter strips?
They often come from extra bundles or specific SKUs. Add a small allowance or follow your product guidance.
Roof squares, bundles, and why pitch matters
Roof takeoffs hinge on two truths: the actual sloped area is larger than the horizontal footprint, and nearly every roof incurs waste. Our calculator packages these realities into a quick, repeatable estimate you can use to plan materials and sanity-check quotes.
From footprint to sloped area
When we enter a building footprint (length × width), we start with the horizontal area in square feet. The roof’s incline stretches that area along the slope. If the pitch is 6/12, the rise is 6 inches for every 12 inches of run. The geometric multiplier is √(1 + (rise/12)²). Multiply this by the footprint to estimate the sloped surface.
Waste and complexity
Waste covers offcuts, course alignment, rakes, ridge, and penetrations like vents, skylights, or chimneys. Hip and valley roofs consume more material than simple gables. As a rule of thumb, 7–15% is common, while ornate roofs may exceed 20%. Ordering slightly extra helps avoid mid-job shortages that can introduce color lot mismatches.
Bundles and coverage
Most asphalt shingles sell by the bundle with an effective coverage printed on the wrapper—commonly about 33.3 ft². Three bundles approximate one square (100 ft²). Because coverage can vary by manufacturer, always confirm the exact number before finalizing an order.
Nails and underlayment
Nail counts depend on shingle type, exposure, and local code. Four nails per shingle is typical; high-wind zones often require six. Underlayment coverage depends on material and overlap. We offer three common options with typical effective coverage values after overlaps.
Common field adjustments
- Include overhangs in your L×W when possible—eaves and rakes add area.
- Steep roofs may require safety gear and more time; labor estimates should scale accordingly.
- Color lots can differ; keep a spare bundle for future repairs.
- Local code can change nailing, underlayment, and ice-barrier requirements—verify before you buy.
Quality control and inspections
Before installation, inspect the deck for rot or delamination. Replace compromised sheathing, fix protruding fasteners, and ensure proper attic ventilation. After installation, check for straight courses, correct exposure, and clean cuts at valleys and rakes.
Estimating like a pro
- Measure or retrieve as-built plans for footprint dimensions.
- Determine pitch from a safe vantage or with a pitch tool.
- Compute sloped area and adjust for waste by roof style.
- Confirm bundle coverage on the product wrapper.
- Order nails, underlayment, and accessories with a small buffer.
Beyond shingles: accessories to remember
- Starter strips and ridge caps (sometimes cut from extra shingles).
- Drip edge, valley flashing, step flashing, and pipe boots.
- Ice and water shield in eave/valley zones where required.
- Ventilation components: ridge vents, box vents, or turbines.
Final thoughts
Our goal is a dependable baseline estimate that keeps jobs moving. Use the live results to align scope, cost, and delivery timing, then finalize with product-specific specs and local code.