Project Inputs
White theme
Used to convert R targets to thickness.
Typical: Closed ~6.5, Open ~3.7
Covers losses, overspray, start/stop waste.
Rated yield at lab conditions.
Used when "Custom" is selected above.
Job conditions factor. Example: 90% of rated yield.
Used to estimate material cost.
Areas to Spray
| Label | Dim A (ft) | Dim B (ft) | Openings (ft²) | Area (ft²) | Use R? | Thickness (in) | R target | Board feet |
|---|
Tip: Area = Dim A × Dim B − Openings. If "Use R?" is checked, thickness is computed from the R target and the selected R per inch.
Results
Total area0.00 ft²
Raw board feet0.00 bf
After waste0.00 bf
Effective per kit0.00 bf/kit
Kits required0
Material cost—
Example Data
| Label | Dim A | Dim B | Openings | Thk |
|---|---|---|---|---|
| Wall 1 | 40 | 9 | 50 | 2.0 |
| Attic Roof | 40 | 30 | 0 | 3.0 |
| Rim Joists | 120 | 1 | 0 | 2.0 |
Click Load example data to populate rows with these values.
Formula Used
Board feet (bf) = Area(ft²) × Thickness(in) ÷ 12
Area(ft²) = DimA(ft) × DimB(ft) − Openings(ft²)
Thickness(in) = R target ÷ R per inch
Effective kit coverage = Kit yield × Derate%.
Total with waste = Raw bf × (1 + Waste%).
Kits = Ceiling(Total with waste ÷ Effective kit coverage).
Area(ft²) = DimA(ft) × DimB(ft) − Openings(ft²)
Thickness(in) = R target ÷ R per inch
How to Use This Calculator
- Select foam type and verify the R per inch value.
- Enter kit yield, derate percent, and optional kit cost.
- Add areas: provide Dim A, Dim B, openings, and either thickness or an R target.
- Toggle Use R? to auto convert R target to thickness using R per inch.
- Adjust waste percent to reflect overspray and cutting losses.
- Review results: raw and after-waste board feet, effective per kit, kits required, and cost.
- Use Download CSV or Download PDF for records and sharing.
FAQs
A board foot is a volume unit equal to one square foot at one inch thickness. This calculator multiplies area by thickness and divides by twelve to get board feet.
Cold substrates, low canister temperatures, and windy conditions reduce expansion and yield. Use the derate percentage to reflect realistic coverage under your job conditions.
R targets are convenient for code or energy goals. Thickness is direct. If you provide an R target, the calculator converts it using the selected R per inch value.
Typical closed cell foams are around R‑6 to R‑7 per inch. Open cell foams are around R‑3.5 to R‑3.8 per inch. Check your product data sheet for exact values.
Ten percent is a common starting point. Increase for complex geometry, tight access, high overspray risk, or inexperienced crews. Reduce for simple runs or experienced application teams.
Yes. The tool rounds up to whole kits because partial kits are not practical. Consider an extra kit for contingencies and test sprays if the project is critical.
Enter a kit cost to estimate material costs. The calculator multiplies required kits by the given cost. It does not include labor, equipment, or mobilization costs.
Enter the target R value per area. The tool converts to thickness using your chosen R per inch. Always verify with local codes and product approvals.
Use Dim A and Dim B for rectangles. Subtract openings for doors, windows, or penetrations. For complex shapes, split them into smaller rectangles and add multiple rows.
Download CSV or PDF after entering your data. You can also print the page. For persistent storage, copy the CSV to your project files or estimating software.