Calculator Form
Example Data Table
| Category | Name | Qty | Width | Height | Computed Area |
|---|---|---|---|---|---|
| Wall | Front Wall | 1 | 40 ft | 10 ft | 400 ft² |
| Wall | Back Wall | 1 | 40 ft | 10 ft | 400 ft² |
| Wall | Left Wall | 1 | 30 ft | 10 ft | 300 ft² |
| Wall | Right Wall | 1 | 30 ft | 10 ft | 300 ft² |
| Gable | Front Gable | 1 | 30 ft | 6 ft | 90 ft² |
| Gable | Back Gable | 1 | 30 ft | 6 ft | 90 ft² |
| Opening | Garage Door | 1 | 16 ft | 7 ft | 112 ft² |
| Opening | Entry Door | 1 | 3 ft | 7 ft | 21 ft² |
| Opening | Window | 8 | 3 ft | 4 ft | 96 ft² |
| Net Siding Area | 1,351 ft² | ||||
Formula Used
Wall Area = Quantity × Width × Height
Gable Area = Quantity × (Base Width × Gable Height ÷ 2)
Opening Area = Quantity × Width × Height
Net Area = (Total Wall Area + Total Gable Area) − Total Opening Area
Waste Area = Net Area × Waste Percentage
Order Area = Net Area + Waste Area
How to Use This Calculator
- Select feet or meters for the project.
- Enter waste percentage, coverage per box, and pricing details.
- Add every rectangular wall row with quantity, width, and height.
- Add each gable separately using base width and triangle height.
- Enter all windows, doors, garage doors, and other openings.
- Optionally enter starter strip and corner post pricing.
- Press Calculate Siding Area to show results above the form.
- Review the summary, area breakdown, graph, then download CSV or PDF.
Frequently Asked Questions
1. What does this siding area calculator estimate?
It estimates gross wall area, opening deductions, waste allowance, order area, boxes needed, siding pieces, starter strips, and a simple total project cost.
2. Should I subtract windows and doors?
Yes. Most takeoffs subtract larger openings because they reduce installed siding area. This calculator includes a separate openings section for that deduction.
3. Why is waste percentage important?
Waste covers offcuts, breakage, mistakes, pattern alignment, and spare pieces for future repairs. Complex elevations usually need more waste than simple rectangular walls.
4. How are gables calculated here?
Each gable is treated as a triangle. The calculator uses base width multiplied by gable height, then divides by two before multiplying by quantity.
5. What is coverage per box?
Coverage per box is the manufacturer’s stated installed area from one carton or bundle. Use the product label value for better material counts.
6. Can I use metric measurements?
Yes. Switch the unit system to meters. The calculator updates labels and treats all entered dimensions and area coverage in metric terms.
7. Does this replace a contractor takeoff?
No. It gives a strong planning estimate, but field conditions, trim complexity, corner details, and brand-specific installation rules still affect final orders.
8. Can I download my results?
Yes. After calculation, use the CSV button for spreadsheet-friendly data or the PDF button for a printable summary and graph snapshot.