Calculator
Tip: For greenhouse walls and ceilings, measure each surface separately to reduce waste.
Example data table
| Section | Length | Width | Qty |
|---|---|---|---|
| Frost row cover | 8.00 | 1.20 | 2 |
| Greenhouse wall | 6.00 | 2.20 | 1 |
| Bench skirt | 4.00 | 0.80 | 3 |
These are sample sections you can load using the button in the calculator.
Formula used
- Section area = length × width × quantity
- Base area = sum of all section areas
- Effective roll width = roll width × (1 − overlap%/100)
- Coverage per roll = effective roll width × roll length
- Adjusted required area = base area × layers × (1 + waste%/100)
- Rolls needed = ceil(adjusted required area / coverage per roll)
- Leftover coverage = rolls needed × coverage per roll − adjusted required area
All calculations use a single unit system internally, then display the chosen unit.
How to use this calculator
- Select your measurement unit and input method.
- Enter your roll width and roll length from the packaging.
- Add overlap percent if you plan to seam or tape edges.
- Add waste percent for trimming around hoops, doors, and vents.
- Set layers to model double wrapping or extra frost protection.
- Enter price per roll for a quick budget estimate.
- Press Calculate to show results above the form.
- Use Download CSV or Download PDF to save your results.