Siding Material Calculator
Exterior cladding takeoff
Enter surfaces, openings, product coverage, and accessories
Result
Calculation summary
Enter values to see the result
Siding elevation preview
Walls, gable, openings, and order quantity
Gross surface area
390 ft²
Net siding field area
345 ft²
Required siding packages
2
The drawing explains the measurement model; it is not a scaled elevation, installation detail, or wall-assembly design.
How to use this calculator
- 1Break the exterior into non-overlapping rectangular walls and triangular gables, then enter every surface in its own measurement unit.
- 2Add windows, doors, and other openings, and choose whether to deduct them or leave them included as part of the field allowance.
- 3Enter the exact coverage printed on a package, or use the installed exposed width and stock length for products purchased by the piece.
- 4Add project-specific waste, optional housewrap and accessory stock, and current material prices before reviewing the whole-unit order.
Formula
Required area = (rectangle areas + ½ × gable bases × heights − deducted openings) × (1 + waste %)
Packages are rounded up from manufacturer-stated package coverage; piece mode uses installed exposed width multiplied by stock length. One siding square is shown as exactly 100 ft² (9.290304 m²).
Calculation steps
- Convert each entered width and height to meters and calculate rectangular or triangular surface area.
- Calculate opening groups by width × height × quantity and subtract them only when the deduction option is enabled.
- Apply siding waste to the net field area and convert the result to both the selected area unit and 100 ft² siding squares.
- Divide required area by package coverage or exposed-face piece coverage, then round up to a whole purchase quantity.
- Estimate housewrap rolls, starter strips, and trim pieces independently from their entered coverage or stock lengths.
- Total only the optional material prices entered by the user.
Worked example
A 30 ft × 10 ft wall plus a 30 ft × 6 ft triangular gable has 390 ft² gross area. Deducting two 3 ft × 4 ft windows and one 3 ft × 7 ft door leaves 345 ft²; 10% waste produces 379.5 ft², or 3.795 siding squares and two 200 ft² packages.
Assumptions
- Surfaces are flat non-overlapping rectangles or triangles; dormers, bays, curves, gambrels, shared areas, and irregular shapes must be split and checked separately.
- The opening option is a planning choice: some estimating practices leave ordinary windows and doors included as allowance, while other workflows deduct measured openings and add explicit waste.
- Package coverage, exposed width, stock length, orientation, minimum laps, end joints, fastening, clearances, flashing, drainage, and compatible accessories come from the selected manufacturer system.
- Housewrap and accessory counts use simple coverage or linear-stock division and do not lay out seams, overlaps, corners, penetrations, or profile-specific pieces.
- The tool does not select cladding, design wall assemblies, check fire/wind/moisture requirements, or determine permits and code compliance.
- Labor, delivery, tax, scaffolding, demolition, substrate repair, fasteners, flashing, caulk, soffit, fascia, and specialty trim are excluded unless represented by an entered price.
Sources
Frequently asked questions
What is a siding square?
A siding square is an ordering-area term equal to 100 square feet, or 9.290304 square meters. It is not necessarily one carton: the number of squares per carton depends on the product.
Should windows and doors be deducted?
Either convention can be valid for planning. Leave them included when they intentionally serve as an allowance, or deduct measured openings and add an explicit waste percentage. Very large openings deserve individual review.
Why does piece mode use exposed width instead of total board width?
Lap and interlocking products cover only their installed exposed face. Using total manufactured width would overstate coverage.
Does the package count include trim and housewrap?
No. Siding, housewrap, starter strip, and trim are calculated independently because their packaging and measurement bases differ.
Can this calculator design the exterior wall assembly?
No. Water, air, thermal, fire, wind, fastening, flashing, and clearance details must follow the selected system and applicable local requirements.
Does estimated cost include installation?
No. It totals only the material unit prices entered in the calculator.