Pond Liner & Underlayment Calculator | LandscapeCalculating.com

Pond Liner & Underlayment CalculatorCalculate EPDM or PVC pond liner dimensions and underlayment area for any pond or stream, including overlap, shelf and depth allowance.Free pond liner & underlayment calculator with formulas, waste factors, cost estimates and professional guidance.Formula: liner length = pond length + 2 × depth + 2 × shelves + 2 × overlap; liner sq ft = liner L × liner WHow to use this calculator

Enter the pond longest and widest dimensions and the maximum depth.

Add a shelf allowance if the pond has planting shelves, and keep 2 ft of edge overlap.

Buy the next standard roll size up rather than seaming in the field.

Frequently asked questions

How do I calculate what size pond liner I need?

Add twice the maximum depth plus shelf allowance plus 2 ft of overlap to both the length and width. This tool returns the exact liner and underlayment dimensions.

How much underlayment do I need for a pond?

Match the underlayment square footage to the liner square footage — never skip it, since a single sharp stone can puncture a liner.

Should I seam a pond liner or buy a bigger one?

Buy the next size up. Field seams are the most common leak point in garden ponds, and a single oversize liner is faster and more reliable.

How much does a pond liner cost?

EPDM pond liner runs about $0.70–$1.10 per sq ft; this calculator multiplies your liner square footage by the per-foot price for a material estimate.

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