Roofing Calculator – How Many Shingles Do I Need?
Calculate roofing shingles, bundles, and squares needed for your roof replacement
Roofing Shingle Calculator
Pitch multiplier increases actual roof surface area
⚡ Quick Answer
One roofing square covers 100 square feet and requires 3 bundles of standard 3-tab shingles. Our calculator accounts for roof pitch, waste factor, and provides material estimates.
Planning a roof replacement or repair? Knowing exactly how many shingles to order prevents costly delays and overordering. This calculator factors in roof pitch (which increases actual surface area) and includes proper waste allowance for cuts and mistakes.
Dr. Snezana Lawrence
Mathematical Historian
15+ years experience
PhD from Yale University. Published mathematical historian ensuring precision in all calculations.
Education
PhD in Mathematical History - Yale University
Understanding Roofing Measurements
1 Square = 100 sq ft
The standard unit for measuring roofing materials
1 Bundle ≈ 33 sq ft
Standard coverage for 3-tab shingles
3 Bundles = 1 Square
3 bundles cover 100 sq ft
29 Shingles per Bundle
Standard count for 3-tab shingles
Pitch Increases Area
Steeper roofs have more surface area
How Roof Pitch Affects Material Needs
| Pitch | Multiplier | 1000 sq ft Base | Increase |
|---|---|---|---|
| Flat (0/12) | ×1.00 | 1,000 sq ft | -- |
| 4/12 | ×1.05 | 1,050 sq ft | +5% |
| 6/12 (Standard) | ×1.12 | 1,120 sq ft | +12% |
| 8/12 | ×1.20 | 1,200 sq ft | +20% |
| 12/12 (45°) | ×1.41 | 1,410 sq ft | +41% |
How Many Shingles in a Bundle?
3-Tab Shingles
- • ~29 shingles per bundle
- • 3 bundles per square
- • Most economical option
- • 15-20 year lifespan
Architectural Shingles
- • ~21 shingles per bundle
- • 4 bundles per square
- • Dimensional appearance
- • 25-30 year lifespan
Laminated Shingles
- • ~15 shingles per bundle
- • 4-5 bundles per square
- • Premium look
- • 30-50 year lifespan
Always check manufacturer specifications for exact counts.
Frequently Asked Questions
How many bundles of shingles do I need for 1200 square feet?
For a flat roof: 1200 ÷ 100 = 12 squares × 3 bundles = 36 bundles. Add 10% waste = 40 bundles. Adjust for pitch.
How do I measure my roof for shingles?
Measure length × width at ground level, then multiply by pitch factor. For complex roofs, measure each plane separately and add together.
How much waste should I add for shingles?
Add 10% for simple gable roofs, 15% for hip roofs, and 20% for complex roofs with valleys and dormers.
What's the difference between 3-tab and architectural shingles?
3-tab shingles are flat, lighter, and cheaper. Architectural shingles are thicker, dimensional, last longer, and require 4 bundles per square instead of 3.
How many squares is a 2000 square foot house?
It depends on roof pitch and overhang. A simple gable roof on 2000 sq ft house is typically 22-26 squares including pitch and waste.
Do I need underlayment for the entire roof?
Yes, underlayment should cover the entire roof deck. Order the same square footage as your shingles (before waste factor).
Dr. Snezana Lawrence
Mathematical Historian | PhD from Yale
Dr. Lawrence is a published mathematical historian with a PhD from Yale University. She ensures mathematical precision and accuracy in all our calculations, conversions, and academic score calculators. Her expertise spans computational mathematics and educational assessment.
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