Roofing Square Footage Calculator (Roof Area, Squares, and Bundles)
If you’re planning a roofing job in Terre Haute or anywhere in West-Central Indiana, the fastest way to avoid under-ordering is to estimate roof area the same way roofers do: start with the roof’s footprint (including overhangs) and apply a pitch (slope) factor. This calculator gives you roof square footage, roofing squares, and an estimated bundle count with waste included.
If you want a real quote (not just an estimate), we can measure your roof, confirm details like valleys/dormers, and give you a clear scope: Construction Company in Terre Haute
Use the calculator
Roof Area Calculator
Calculates roof surface area using plan area (including overhangs) × pitch factor. Outputs square footage, squares, and bundles.
Inputs
Results
Estimator only. Roofs with dormers, multiple valleys, complex hips, steep pitch, multiple layers, or decking repairs can change totals. If you want an exact number, we’ll measure it and confirm details before you order materials.
How the math works (simple and accurate for most roofs)
This tool uses a reliable estimating method: take the horizontal roof footprint area (length × width), add overhangs, then multiply by a pitch factor that accounts for slope. That gives you total roof surface area.
- Plan length = building length + (2 × gable/rake overhang)
- Plan width = building width + (2 × eave overhang)
- Plan area = plan length × plan width
- Pitch factor = √(run² + rise²) ÷ run
- Roof area = plan area × pitch factor
- Total with waste = roof area × (1 + waste%)
Pitch factor table (quick reference)
If you want to sanity-check your results, these are common pitch factors for “rise per 12” roof pitches.
| Pitch | Factor | Pitch | Factor |
|---|---|---|---|
| 3/12 | 1.031 | 8/12 | 1.202 |
| 4/12 | 1.054 | 9/12 | 1.250 |
| 5/12 | 1.083 | 10/12 | 1.302 |
| 6/12 | 1.118 | 12/12 | 1.414 |
Waste guidelines (planning ranges)
Waste depends on roof complexity. A simple gable roof needs less waste than a roof with multiple valleys, dormers, and cut-ups. These are practical ranges for planning before an on-site measurement.
| Roof type | Typical waste | Why it changes | Planning note |
|---|---|---|---|
| Simple gable | 7–10% | Fewer cuts and fewer valleys | Use 10% if you’re unsure |
| Hip / moderate complexity | 10–15% | More angles and more layout cuts | Use 12–15% for most hipped roofs |
| Valleys, dormers, cut-ups | 15–20% | Lots of waste from short runs and angles | Measure first if ordering tight |
| Steep pitch / specialty details | 15–25% | Higher loss and extra starter/ice details | Budget higher until confirmed |
When you should get an exact measurement
This calculator is great for budgeting and rough ordering. But if any of the items below apply, an on-site measurement is the smart move before you buy materials.
- Multiple dormers, valleys, or complex roof lines
- Very steep pitch or hard-to-access areas
- Multiple layers that require tear-off planning
- Suspected decking damage or ventilation changes
- New gutters/soffit/fascia planned at the same time
- Insurance scope with exact squares required
Want a Real Number for Your Roof?
If you want an estimate that’s actually useful, the goal is simple: clear scope, realistic allowances, and a timeline you can plan your life around. We can measure your roof, confirm pitch/overhangs/complexity, and give you a straightforward plan so you know what to expect.
Serving Terre Haute, Vigo County, Clinton, Rockville, and surrounding areas.
