Roofing Square Footage Calculator
Get roof square footage, number of roofing squares, and shingle bundles needed for any simple gable or hip roof — with a built-in pitch multiplier.
Pitch is rise/run. A 5/12 pitch rises 5 inches every 12 inches of run.
10% for simple gable roofs; 15% for hip roofs and complex layouts.
Results
Roofing is sold in "squares": 1 square = 100 sq ft of coverage. Asphalt shingles come 3 bundles to a square. Synthetic underlayment typically covers ~400 sq ft per roll.
Roof Pitch Multipliers Reference
Pitch describes how steep the roof is, expressed as rise over a 12-inch horizontal run. The multiplier converts the building footprint area into actual roof surface area.
| Pitch (rise/12) | Surface Multiplier | Equivalent Angle |
|---|---|---|
| 1/12 (flat) | 1.003 | 4.8° |
| 3/12 (low) | 1.031 | 14.0° |
| 4/12 (standard) | 1.054 | 18.4° |
| 5/12 (standard) | 1.083 | 22.6° |
| 6/12 (standard) | 1.118 | 26.6° |
| 7/12 (steep) | 1.158 | 30.3° |
| 8/12 (steep) | 1.202 | 33.7° |
| 10/12 (very steep) | 1.302 | 39.8° |
| 12/12 (45°) | 1.414 | 45.0° |
Roofing Material Yields
3-Tab Asphalt Shingles
3 bundles per square. Most economical option, 20–25 year warranty typical. Roughly $90–150 per square installed.
Architectural Shingles
3–4 bundles per square. Thicker dimensional appearance, 30-year warranty. About $130–200 per square installed.
Metal Roofing Panels
Sold by linear foot of panel; calculate roof area, then divide by panel width and order full lengths. 40–70 year service life.
Synthetic Underlayment
1 roll covers ~400 sq ft. Required beneath all shingle types. Replaces traditional 15 lb felt.
2026 Roofing Cost Guide
Installed cost per roofing square (100 sq ft) varies by material, region, and roof complexity. Use these ranges as a planning budget — get 3 local quotes before committing.
| Material | Per Square (100 sq ft) | Lifespan |
|---|---|---|
| 3-Tab Asphalt | $350–550 | 20–25 yrs |
| Architectural Asphalt | $450–700 | 30 yrs |
| Metal (standing seam) | $800–1,400 | 40–70 yrs |
| Synthetic Slate | $1,000–1,800 | 50+ yrs |
Cost ranges include materials, labor, underlayment, and basic flashing for a straightforward gable roof on a single-story home. Steep pitches, multi-plane roofs, and tear-off of old layers add 20–50%.
Calculating for Complex Roofs
If your roof has multiple sections (dormers, gables, L- or T-shaped footprint), calculate each rectangular section as its own roof, then add the results together:
- Divide the roof into individual rectangular sections.
- For each section, measure length × width (the footprint of that section only).
- Apply the pitch multiplier that matches each section's slope.
- Add 15% waste (hip roofs need more material for cuts at valleys and ridges).
- Sum all section totals — that is your complete roof area.
Example: L-shaped house
Main section: 40 × 30 ft × 1.083 (5/12 pitch) = 1,300 sq ft × 1.15 (waste) = 1,495 sq ft
Wing section: 20 × 16 ft × 1.083 (5/12 pitch) = 347 sq ft × 1.15 (waste) = 399 sq ft
Total: 1,894 sq ft = 18.9 squares → order 57 bundles of 3-tab shingles
Frequently Asked Questions
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Sources
The figures on this page are based on data from these authoritative industry sources.
- The Home Depot Buyer’s Guides — Retail price ranges for flooring, paint, and finishing materials.