Siding Calculator
Calculate siding material quantities for your home exterior project with opening deductions and waste factor.
Part of the Roofing & Structure calculators — see all tools in this category.
Current result
Total exterior wall area
Total area of all windows and doors combined
Standard 10%, increase for complex layouts (5-15%)
1 square = 100 sq ft of wall coverage. This is the standard ordering unit for vinyl siding. When ordering, round up — leftover material can be saved for future repairs.
Results
The link includes your entered calculation values. Base64 makes the URL portable; it is not encryption.
Squares (100 sq ft)
After opening deductions
10% waste applied
Bottom edge trim
Around windows/doors
Frequently Asked Questions
How it works and assumptions
- 1. Measure Wall Area
Measure the height and width of each exterior wall, or estimate the total square footage. For per-wall input, the calculator sums each wall's area (height × width) automatically.
- 2. Deduct Openings
Subtract the total area of all windows and doors. Measure each opening and add them together. A standard window is about 15 sq ft and a door about 21 sq ft.
- 3. Select Siding Type
Vinyl siding is measured in squares (100 sq ft), fiber cement in boards (12 ft planks), and wood lap in board-feet. The calculator adjusts output units based on your selection.
- 4. Apply Waste Factor
A 10% waste factor is standard for most homes. Increase to 12-15% for complex layouts with many corners, gables, or dormers. The calculator adds this to the net area before computing material quantities.
- 5. Add Accessories
Starter strip runs along the bottom edge of all walls (equals house perimeter). J-channel frames all window and door openings. Both are estimated based on your inputs.