Weed Barrier / Landscape Fabric Calculator
Calculate rolls of landscape fabric needed from garden bed dimensions in feet or meters.
Returns square footage, roll count with 10% overlap, and staple count.
Landscape weed barrier (ground cloth / weed fabric) blocks sunlight to prevent weed germination while allowing water and air to pass through. Accurate coverage calculation prevents costly mid-project shortages.
Coverage formula:
Area to Cover (sq ft) = Total Bed Area − Area of Existing Plants
Rolls Needed = Area to Cover / (Roll Width × Roll Length)
Overlap allowance: Add 10–20% extra for edge overlaps (typically 6–12 inches between strips), rocks, and cutting waste:
Adjusted Area = Area to Cover × 1.15
Worked example: A garden bed 15 ft × 25 ft = 375 sq ft total
- Existing shrub areas: 3 × 4 ft circles = 37.7 sq ft
- Net coverage needed: 375 − 37.7 = 337.3 sq ft
- With 15% overlap waste: 337.3 × 1.15 = 388 sq ft needed
- Standard roll: 3 ft × 100 ft = 300 sq ft → buy 2 rolls (600 sq ft; leftover useful for future beds)
Weed barrier types and lifespans:
| Type | Lifespan | Water Flow | Best Use |
|---|---|---|---|
| Woven polypropylene | 5–20 years | Good | Permanent beds, pathways |
| Non-woven spunbond | 3–5 years | Excellent | Vegetable gardens |
| Plastic sheeting | 1–3 years | None (except holes) | Solarization, raised beds |
| Biodegradable jute | 1–2 years | Excellent | Eco-friendly short-term use |
Mulch layer required on top: Weed barrier alone still allows weed seeds to germinate in surface dirt. Always top with 2–4 inches of mulch to suppress light and soil erosion.
Staple spacing: Use landscape fabric staples every 12 inches along edges and every 18 inches through the middle. In windy areas, reduce to 8–10 inches at all edges.
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This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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