Roofing Calculator
Calculate roofing materials needed: shingle bundles, underlayment, ridge caps, and more. Includes pitch factors, waste percentages, and cost estimates.
Roof Dimensions
Roofing Squares
18.5 squares
Roofing Quick Reference
- 1 square = 100 sq ft
- 3 bundles = 1 square
- 4-6 nails per shingle
- Overlap: 5" exposure
- 4/12 pitch: +5% area
- 6/12 pitch: +12% area
- 8/12 pitch: +20% area
- 12/12 pitch: +41% area
- Always order 10-15% extra shingles for waste, mistakes, and future repairs
- Match ridge cap and starter to your main shingle brand
- In high-wind areas, use 6 nails per shingle instead of 4
- Ice & water shield is required in cold climates at eaves and valleys
- Check local codes for underlayment requirements
Related Calculators
About This Calculator
How many shingles do you need? The Roofing Calculator instantly converts your roof dimensions into the exact quantities of shingles, underlayment, ridge caps, starter strips, and accessories required—with built-in waste factors for your roof's complexity. Stop guessing and overspending or running short mid-project.
Roofing is measured in "squares" (each square = 100 sq ft), and most asphalt shingles come 3 bundles per square. But your actual material needs depend on roof pitch, complexity, valleys, hips, and dozens of other factors. This calculator handles all the math, from simple gable roofs to complex multi-valley designs with dormers and skylights.
Whether you're a homeowner pricing a DIY re-roof, a contractor preparing an accurate bid, or an insurance adjuster estimating storm damage repair, this calculator provides the precise material list you need. Input your roof footprint and pitch, select your complexity level, and get instant quantities with 2026 pricing estimates. We've helped over 50,000 homeowners plan successful roofing projects without material shortages or costly overages.
How to Use the Roofing Calculator
- 1Enter your roof footprint dimensions (length × width of the building footprint, not actual roof).
- 2Select your roof pitch from the dropdown—the calculator applies the correct multiplier automatically.
- 3Choose your roof complexity level: simple gable (5% waste), hip roof (10%), complex multi-valley (15-20%).
- 4In advanced mode, enter ridge length and total edge/eave length for precise accessory calculations.
- 5Input the number of valleys, skylights, and pipe penetrations for additional flashing estimates.
- 6Customize material prices to match your local supplier quotes for accurate cost estimates.
- 7Review the complete materials list: shingles, underlayment, starter strips, ridge caps, and accessories.
- 8Print or save your estimate for contractor bidding or material ordering at the lumberyard.
Understanding Roofing Squares and Bundles
Roofing is measured in "squares" for simplicity:
Key Conversions:
- 1 Roofing Square = 100 square feet of roof area
- 3 Bundles of shingles = 1 Square (most 3-tab and architectural shingles)
- Some premium/designer shingles = 4-5 bundles per square
Example Calculation: Roof footprint: 40' × 30' = 1,200 sq ft Roof pitch: 6/12 (multiply by 1.12) Actual roof area: 1,200 × 1.12 = 1,344 sq ft Add 10% waste: 1,344 × 1.10 = 1,478 sq ft Roofing squares: 1,478 ÷ 100 = 14.78 squares Bundles needed: 14.78 × 3 = 45 bundles (round up)
Why Order Extra:
- Cuts and waste: 5-15% depending on roof complexity
- Future repairs: Save a bundle for storm damage repairs
- Color matching: Same lot ensures color consistency
Roof Pitch and Its Impact on Materials
Roof pitch (slope) affects the actual surface area you need to cover:
Common Roof Pitches:
| Pitch | Rise per 12" Run | Multiplier | Description |
|---|---|---|---|
| 2/12 | 2" | 1.01 | Nearly flat (minimum for shingles) |
| 4/12 | 4" | 1.05 | Low slope |
| 6/12 | 6" | 1.12 | Standard residential |
| 8/12 | 8" | 1.20 | Steeper residential |
| 10/12 | 10" | 1.30 | Very steep |
| 12/12 | 12" (45°) | 1.41 | Maximum common pitch |
How to Measure Pitch:
- Inside attic: Hold level against rafter, measure rise at 12"
- Outside: Use pitch gauge or phone app
- From ground: Count rows of siding or estimate angle
Pitch Affects Installation:
- Under 4/12: Special low-slope underlayment required
- Over 7/12: Safety equipment, slower installation
- Over 12/12: Specialty roofing may be needed
Complete Materials List for Asphalt Roofing
A complete roofing job requires more than just shingles:
Primary Materials:
| Material | Coverage | Purpose |
|---|---|---|
| Shingles | 3 bundles/square | Primary waterproofing |
| Underlayment | 1 roll/10 squares | Secondary waterproofing |
| Starter strip | 1 bundle/105 lin ft | Edge seal, wind resistance |
| Ridge cap | 1 bundle/35 lin ft | Hip and ridge coverage |
| Drip edge | 10' pieces | Edges, protects fascia |
Fasteners and Sealants:
| Material | Quantity | Purpose |
|---|---|---|
| Roofing nails | 2-3 lbs/square | Shingle attachment |
| Cap nails | 1 lb/5 rolls | Underlayment |
| Roofing cement | 1 gal/20 squares | Sealing, repairs |
| Caulk | 2-3 tubes/roof | Flashing, vents |
Flashing and Vents:
| Item | Notes |
|---|---|
| Step flashing | Where roof meets wall |
| Valley flashing | Pre-formed metal or roll |
| Pipe boots | Around plumbing vents |
| Roof vents | Attic ventilation |
| Ice & water shield | Eaves, valleys (cold climates) |
Waste Factors by Roof Complexity
Complex roofs require more material due to cutting and fitting:
Waste Factor Guidelines:
| Roof Type | Waste Factor | Description |
|---|---|---|
| Simple gable | 5% | Two planes, minimal cutting |
| Hip roof | 10% | Four planes, angled cuts |
| L-shaped | 10-12% | Multiple sections |
| Cross gable | 12-15% | Intersecting gables |
| Dormers | 15% | Extra valleys, flashings |
| Multiple valleys | 15-20% | Extensive cutting |
| Skylights | +2-3% each | Additional flashing cuts |
| Complex/historic | 20-25% | Many planes and angles |
What Creates Waste:
- Valley cuts: Shingles trimmed at angles
- Hip cuts: Angled cuts along hips
- Starter courses: Use of partial shingles
- Damaged shingles: Breakage during installation
- Manufacturer defects: Occasional unusable shingles
Reducing Waste:
- Plan shingle layout before starting
- Use cut pieces where possible
- Order full squares (avoid partial bundles)
- Return unopened bundles
DIY vs. Professional Installation
Consider the trade-offs before deciding:
DIY Roofing:
Potential Savings: 40-60% (labor is about half the cost)
Requirements:
- Comfort working at heights
- Physical fitness for heavy lifting
- Time: 2-4 days for average roof (2-3 people)
- Tools: nail gun, ladders, scaffolding, safety gear
Best For:
- Simple gable roofs
- Single-story homes
- Moderate pitch (4/12 to 7/12)
- New construction (no tear-off)
Professional Installation:
Typical Costs (2026):
- Tear-off: $50-75/square
- Installation: $75-125/square
- Total: $125-200/square (materials extra)
Benefits:
- Manufacturer warranty requirements met
- Faster completion (1-2 days typical)
- Proper flashing and ventilation
- Insurance for worker injuries
- Warranty on workmanship
When to Hire a Pro:
- Steep roofs (over 7/12 pitch)
- Multi-story homes
- Complex roof designs
- Structural repairs needed
- Local code requires licensed installer
2026 Roofing Material Costs
Material prices vary by region and quality level. Here are typical 2026 prices:
Asphalt Shingles:
| Type | Cost per Bundle | Cost per Square | Warranty |
|---|---|---|---|
| 3-Tab Standard | $28-35 | $84-105 | 20-25 years |
| Architectural Standard | $35-45 | $105-135 | 30 years |
| Architectural Premium | $45-65 | $135-195 | Lifetime |
| Designer/Luxury | $80-150 | $240-450 | Lifetime |
Underlayment:
| Type | Cost per Roll | Coverage | Best For |
|---|---|---|---|
| #15 Felt | $20-25 | 400 sq ft | Budget, moderate climates |
| #30 Felt | $30-40 | 200 sq ft | Better protection |
| Synthetic | $75-125 | 1,000 sq ft | Premium, walkable |
| Ice & Water | $100-150 | 200 sq ft | Cold climates, valleys |
Accessories:
| Item | Unit Cost | Notes |
|---|---|---|
| Starter strip | $25-40/bundle | 105 linear feet |
| Ridge cap | $40-60/bundle | 35 linear feet |
| Drip edge | $8-15/10 ft | Aluminum or galvanized |
| Step flashing | $15-25/pack | 10 pieces |
| Pipe boots | $10-20 each | Rubber or lead |
Total Cost Estimates (Materials Only):
| Roof Size | Simple Gable | Hip Roof | Complex |
|---|---|---|---|
| 1,500 sq ft | $3,000-4,500 | $3,500-5,000 | $4,000-6,000 |
| 2,000 sq ft | $4,000-6,000 | $4,500-6,500 | $5,500-8,000 |
| 2,500 sq ft | $5,000-7,500 | $5,500-8,500 | $7,000-10,000 |
Asphalt Shingle Types Compared
Understanding shingle types helps you choose the right product:
3-Tab Shingles:
- Flat, uniform appearance with 3 tabs per shingle
- Lightest weight (typically 210-240 lbs/square)
- Most economical ($25-35/bundle)
- 20-25 year warranties
- Wind rating: 60-70 mph
- Best for: Budget projects, rentals, sheds
Architectural (Dimensional) Shingles:
- Layered, textured, dimensional look
- Heavier (240-340 lbs/square)
- Mid-range ($35-75/bundle)
- 30-50 year warranties
- Wind rating: 110-130 mph
- Best for: Most residential applications
Designer/Luxury Shingles:
- Premium appearance mimicking slate, wood, or tile
- Heaviest (350-400+ lbs/square)
- Premium price ($80-150/bundle)
- Lifetime warranties (50+ years prorated)
- Wind rating: 130+ mph
- Best for: High-end homes, curb appeal focus
Impact-Resistant Shingles:
- Class 4 impact rating (highest)
- Withstands 2" hail without damage
- 10-30% insurance discounts in hail-prone areas
- $40-80/bundle
- Required or recommended in many areas
Cool Roof Shingles:
- Reflective granules reduce heat absorption
- Can lower attic temps 20-30°F
- May qualify for energy rebates
- $5-10 more per bundle
- Ideal for hot climates
Roof Ventilation Requirements
Proper ventilation extends roof life and prevents problems:
Why Ventilation Matters:
- Reduces attic temperatures (up to 40°F cooler)
- Prevents ice dams in cold climates
- Removes moisture that causes rot and mold
- Extends shingle life by 25-50%
- Required by building codes
Ventilation Requirements: The standard rule: 1 sq ft of vent area per 150 sq ft of attic floor (with vapor barrier) or 1:300 without.
| Attic Size | Minimum Vent Area | Ridge Vent Length |
|---|---|---|
| 1,000 sq ft | 7 sq ft | 35 lin ft |
| 1,500 sq ft | 10 sq ft | 50 lin ft |
| 2,000 sq ft | 13 sq ft | 65 lin ft |
| 2,500 sq ft | 17 sq ft | 85 lin ft |
Intake vs. Exhaust:
- Split 50/50 between intake (soffit) and exhaust (ridge)
- Intake at low points, exhaust at high points
- Never mix powered and passive exhaust vents
Common Vent Types:
| Type | NFVA per Unit | Cost |
|---|---|---|
| Soffit vent (8"x16") | 65 sq in | $3-8 |
| Continuous soffit | 9 sq in/lin ft | $2-4/ft |
| Ridge vent | 18 sq in/lin ft | $3-6/ft |
| Roof louver | 50-75 sq in | $15-30 |
| Gable vent | 150-300 sq in | $20-50 |
| Power vent | 1,000+ CFM | $100-300 |
Warning Signs of Poor Ventilation:
- Ice dams in winter
- Excessive attic heat in summer
- Curling or buckled shingles
- Mold or mildew in attic
- Premature shingle failure
Metal vs. Asphalt: Making the Right Choice
When considering a roof replacement, compare metal and asphalt options:
Asphalt Shingles:
| Factor | Details |
|---|---|
| Initial Cost | $3-7/sq ft installed |
| Lifespan | 20-50 years |
| Weight | 2-4 lbs/sq ft |
| Maintenance | Moderate |
| Wind Rating | 60-130 mph |
| Energy Efficiency | Standard (cool roof options) |
Metal Roofing:
| Factor | Details |
|---|---|
| Initial Cost | $7-15/sq ft installed |
| Lifespan | 40-70+ years |
| Weight | 1-1.5 lbs/sq ft |
| Maintenance | Low |
| Wind Rating | 140+ mph |
| Energy Efficiency | Excellent (reflects heat) |
When to Choose Metal:
- Coastal areas with high winds and salt air
- Fire-prone regions (Class A fire rating)
- Low-slope roofs (standing seam)
- Long-term ownership plans
- Hot climates (energy savings)
When to Choose Asphalt:
- Budget-conscious projects
- Traditional neighborhood aesthetics
- DIY-friendly installation
- Shorter ownership timelines
- Easy repair/replacement
Total Cost of Ownership (30 years):
- Asphalt: May need 1-2 replacements = $15,000-40,000
- Metal: One installation + maintenance = $12,000-25,000
Pro Tips
- 💡Always order 10-15% extra shingles for waste and future repairs—keeping one bundle ensures color-matched replacement for storm damage.
- 💡Match shingles from the same manufacturing lot number to ensure color consistency across your entire roof.
- 💡In high-wind areas (90+ mph zones), use 6 nails per shingle instead of the standard 4 for better wind resistance.
- 💡Store shingle bundles flat (never on edge) to prevent bending and cracking before installation.
- 💡Check weather forecast—install when rain-free for at least 24 hours so shingles can seal properly.
- 💡Never install asphalt shingles in temperatures below 40°F without special cold-weather adhesives.
- 💡Verify your roof deck before covering—OSB and plywood should be dry and free of rot or soft spots.
- 💡Install ice and water shield in valleys, around penetrations, and along eaves (first 24 inches minimum).
- 💡Get multiple quotes from licensed contractors—prices can vary 30-50% for the same job.
- 💡Check contractor licensing, insurance, and reviews before hiring—ask for recent local references.
- 💡Consider impact-resistant shingles if you live in a hail-prone area—they can save 10-30% on insurance.
- 💡Take photos of your old roof before tear-off for insurance documentation and future reference.
Frequently Asked Questions
For a 1,500 sq ft roof footprint, you need to account for pitch and waste. At a typical 6/12 pitch (1.12 multiplier): 1,500 × 1.12 = 1,680 sq ft. Add 10% waste: 1,848 sq ft = 18.5 squares = 56 bundles. Always round up and consider keeping 1-2 extra bundles for future repairs.
