Siding Calculator
Calculate exactly how much siding you need for your house. Enter wall lengths for each side, wall height, and subtract doors and windows. Choose from vinyl, fiber cement, or wood siding with a 10% waste factor built in.
House Perimeter — Wall Lengths
💡 Standard residential wall height is 8–10 ft. Include gable ends separately.
Openings to Subtract
Standard 2-car garage door: ~140 sq ft (16×7 + 18×7 ft avg).
Standard entry door: ~21 sq ft (3×7). Count all exterior doors.
Standard window: ~15 sq ft (3×5). Add all window areas together.
💡 Adjust based on your material and local labor rates.
🏠 All calculations include a 10% waste factor for cuts, corners, trim, and gable-end triangles.
🏠 Siding Estimate Results
How to Use the Siding Calculator
Enter the length of each exterior wall (front, right, back, left) in feet. These four measurements define your house perimeter. Enter the average wall height — for most single-story homes this is 8–10 feet. Then subtract the total square footage of all garage doors, entry doors, and windows (these don't get siding). Select your siding material and adjust the installed cost per square foot to match your local pricing. Click Calculate Siding to see the net wall area, 10% waste adjustment, and total estimated cost.
Siding Materials Comparison
| Material | Cost/sq ft Installed | Lifespan | Maintenance |
|---|---|---|---|
| Vinyl | $3–7 | 20–40 years | Low — wash annually; no painting |
| Fiber Cement | $5–10 | 50+ years | Moderate — repaint every 10–15 years |
| Wood (Cedar) | $6–12 | 20–40 years | High — stain/seal every 3–5 years |
| Engineered Wood | $4–8 | 30–50 years | Moderate — repaint every 10–15 years |
How to Measure for Siding
- Measure each wall separately — Don't assume opposite walls are identical. Older homes often have slightly different dimensions. Measure to the nearest inch.
- Wall height — Measure from the bottom of the siding (above the foundation) to the soffit. For multi-story homes, measure each floor separately and add them.
- Gable ends — For triangular gable ends, use the formula: (base width × height) ÷ 2. Add this area to your gross wall total. Our calculator doesn't include gable ends automatically — add them as extra square footage.
- Don't subtract small things — Electrical outlets, vents, and hose bibs are too small to matter. Only subtract doors, windows, and garage doors (anything over ~4 sq ft).
- Include soffit and fascia — If you're replacing soffit and fascia along with siding, measure linear feet separately. Soffit runs $3–8 per linear foot installed.
Understanding the Waste Factor
A 10% waste factor is standard for siding installation. Here's what it accounts for:
- Cutting waste — Each piece of siding gets cut to fit around windows, doors, and corners. The offcuts are often too short to reuse elsewhere.
- Lap pattern — Most siding is installed with a 1–1.25 inch overlap, which uses slightly more material than the net square footage would suggest.
- Gable waste — Angled cuts for gable ends produce more waste than straight horizontal runs.
- Damage & mistakes — Pieces get dropped, cracked, or miscut. Having extra material prevents work stoppages.
- Future repairs — Keep a box or bundle for future repairs. Siding colors and styles get discontinued.