Pond Liner Calculator

Calculate the size of pond liner needed based on pond dimensions and depth.

Part of:Gardening hub
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How to Use This Calculator

How to Use

  1. Enter pond length, width, and maximum depth.
  2. Adjust the overlap allowance (2 ft / 0.6 m is standard).

Formula

Liner size = Pond dimension + (2 × Max Depth) + (2 × Overlap)

Tips

  • Always use pond underlay beneath the liner to prevent punctures.
  • EPDM and butyl rubber are the most durable liner materials.
  • Allow extra overlap for securing the edges with rocks or edging.

Common Questions

How do I calculate pond liner size?

Add twice the maximum depth plus twice the overlap to both the length and width of the pond.

What thickness liner do I need?

0.75 mm (30 mil) for small ponds, 1.0 mm (40 mil) for medium, and 1.14 mm (45 mil) for large or fish ponds.

Do I need underlay?

Yes – always use a protective underlay (geotextile) beneath the liner to prevent root and stone punctures.

What is the best material for a pond liner?

Butyl rubber and EPDM are the most flexible and longest-lasting, making them ideal for fish ponds. PVC is cheaper but less durable and harder to repair.

How much overlap should a pond liner have?

Allow about 300 mm (1 ft) of liner beyond the edge all round so you can anchor it securely under stones or turf.

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