How deep should a wildlife pond be?

A wildlife pond should have a maximum depth of at least 60cm (2ft) to prevent freezing solid in winter. Include shallow margins (10-20cm) for wildlife access and planting shelves at 20-30cm depth for marginal plants. Varied depths create the best habitat diversity.

What size liner do I need for a pond?

Liner size = pond length + (2 x max depth) + (2 x overlap). The overlap (usually 30cm each side) allows for securing the liner at the edges. Always round up and buy slightly more than calculated to allow for uneven ground.

Do I need a pump for a wildlife pond?

A dedicated wildlife pond does not strictly need a pump if it has a good balance of plants and receives some natural water circulation. However, a pump improves water quality and oxygenation. Size it to circulate half the pond volume per hour.

What is the best shape for a wildlife pond?

An irregular or kidney shape is most natural-looking and provides varied habitat zones. Include at least one gently sloping side for wildlife access, a shallow shelf for marginal plants, and a deeper central zone. Avoid steep sides.

How many plants does a wildlife pond need?

Aim for around two-thirds of the pond surface covered by plants. Include oxygenating plants (one bunch per square metre), marginal plants on the shelves, and a few floating plants. This creates a balanced, low-maintenance ecosystem.

Wildlife Pond Calculator — Volume, Liner & Pump Size

Calculate the volume, liner size, underlay, and pump requirements for a wildlife pond.

Pond Length

Longest span across the water. For a circular pond, enter the diameter here

Pond Width

Widest span across the water. Ignored for circular ponds (the diameter is used instead)

Maximum Depth

Depth at the deepest central zone. Aim for at least 0.6m so a corner stays unfrozen in winter

Pond ShapeIrregular/kidney suits wildlife; the shape sets the average-depth factor used for volume

How We Calculate This

How The Calculations Work

Volume: Length x Width x Depth x shape factor (0.75 rectangular, 0.667 kidney/circular)
Liner: (Length + 2 x depth + 2 x overlap) x (Width + 2 x depth + 2 x overlap)
Pump size: Half the pond volume per hour (litres/hour) — enough to turn over a wildlife/plant pond every 2 hours
Planting shelf: Perimeter x shelf width (an upper-bound estimate — the waterline shelf sits inside the rim and corners overlap, so usable area is a little less)
Shelf depth: Maximum depth x shelf-depth fraction — marginal plants suit 15-25cm of water over the shelf
Circular ponds: The diameter (entered as length) drives volume and a square liner; the width box is ignored

Frequently Asked Questions

Last updated: March 2026

All calculations are estimates based on standard gardening guidelines. Results may vary with soil conditions, climate, and plant varieties.

Wildlife Pond Calculator — Volume, Liner & Pump Size

How We Calculate This

How The Calculations Work

Frequently Asked Questions

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