From measured space to purchasable material
A siding takeoff often needs rectangular wall area plus triangular gables. This calculator handles both, subtracts windows and doors, and rounds the required coverage to cartons using the product’s labeled net coverage. The net figure should account for the panel overlap or reveal specified by the manufacturer; entering raw board area can underestimate the order. This is an area-based estimate for material planning, not a panel cutting schedule. Corners, starter strips, trim, flashings, fasteners and installation details need their own counts.
Measure, select yield and round the order
- Measure rectangular wall runs and gable dimensions.
- Subtract doors and windows once.
- Use installed product coverage and count trim separately.
Net requirement and purchase calculation
A worked example
120 ft of walls at 9 ft plus two 24 × 6 ft gables, minus 180 ft² openings, gives 1,044 ft². With 10% cuts and 100 ft² cartons, purchase 12 cartons.
Siding: what changes the result?
Keep measured geometry separate from coverage, laps and purchase units. The comparisons below are calculated from this page’s default example. Each row changes only the named input; all other inputs stay at their displayed example values. These are mathematical scenarios, not measurements from a completed project.
| Changed assumption | Default input | Comparison input | Result: default → comparison |
|---|---|---|---|
| Total rectangular wall run | 120 ft | 144 ft | Rectangular wall area: 1,080 → 1,296 sq ft Net siding face area: 1,044 → 1,260 sq ft |
| Rectangular wall height | 9 ft | 10.8 ft | Rectangular wall area: 1,080 → 1,296 sq ft Net siding face area: 1,044 → 1,260 sq ft |
| Identical triangular gables | 2 | 3 | Triangular gable area: 144 → 216 sq ft Net siding face area: 1,044 → 1,116 sq ft |
| Gable base width | 24 ft | 28.8 ft | Triangular gable area: 144 → 172.8 sq ft Net siding face area: 1,044 → 1,072.8 sq ft |
Displayed values are rounded. Whole-pack results change in steps; continuous quantities may change before a new pack is needed. To compare your actual project, enter your dimensions above, save a scenario, then change one assumption.
Coverage, allowance and purchasing limits
- Different wall heights or gable sizes need separate takeoffs.
- Very small openings may not yield reusable cuts in an actual panel layout.
- Moisture management, flashing and fastening are separate installation requirements.
Frequently asked questions
Are gables included in siding area?
Yes. Each is treated as a triangle using its horizontal base and vertical rise.
Should carton coverage include overlap?
Use the manufacturer’s net installed coverage after the required overlap or reveal.
Are corner posts and trim included?
No. These depend on linear measurements and the siding system.
Calculation method: JICWH methodology. Examples are planning assumptions, not product recommendations.