Landscape Fabric Calculator Guide
Use this landscape fabric calculator to estimate how many rolls of weed barrier you need. Enter bed area dimensions, roll width and length, and overlap percentage to account for strip layout and seam coverage.
How to use the landscape fabric calculator
Enter the area length and width in feet, your fabric roll width and length in feet, and the overlap percentage between parallel strips (typically 10%).
The calculator returns the number of rolls needed, accounting for effective coverage width after overlap.
Landscape fabric roll formula
Effective roll width = Roll width × (1 − Overlap % ÷ 100). Strips needed = Ceiling(Area width ÷ Effective roll width). Total fabric length = Strips × Area length. Rolls needed = Ceiling(Total length ÷ Roll length).
- Effective width = roll width × (1 − overlap/100)
- Strips = ⌈area width / effective width⌉
- Rolls = ⌈(strips × area length) / roll length⌉
- Add one extra roll for cuts, curves, and overlaps at ends
Worked example
A 20 ft × 10 ft bed covered with 3 ft wide rolls, 50 ft long, with 10% overlap: Effective width = 3 × 0.90 = 2.7 ft.
Strips = ⌈10 ÷ 2.7⌉ = 4. Total length = 4 × 20 = 80 ft. Rolls = ⌈80 ÷ 50⌉ = 2 rolls.
When to use landscape fabric
Woven or non-woven fabric suppresses weeds under gravel paths, rock beds, and some shrub borders. It is less common in active vegetable beds where you dig and amend soil seasonally.
Overlap strips 6–12 inches and pin edges so weeds cannot slip through seams.
Installation tips
Prepare a smooth, debris-free surface before laying fabric. Cut X-slits around existing plants and overlap generously at seams. Cover promptly with mulch or rock so UV does not degrade exposed fabric.
- Use stainless or galvanized fabric staples every 2–3 feet.
- Do not use plastic sheeting where drainage is needed — it traps water.
- Pair with mulch volume calculator for top-layer orders.
- Expect 10–15% extra for irregular bed shapes beyond rectangles.