How Much Pond Liner Do I Need?
Quick Answer
(Length + 2×depth + 0.6m) × (Width + 2×depth + 0.6m)
Example: 3m × 2m pond, 0.6m deep = 4.8m × 3.8m liner (18.24m²)
How We Calculated This
The formula adds the depth twice (to cover both sides) plus an overlap allowance:
- Pond length: 3m, width: 2m, depth: 0.6m
- Liner length: 3 + (2 × 0.6) + 0.6 = 4.8m
- Liner width: 2 + (2 × 0.6) + 0.6 = 3.8m
- Liner area: 4.8 × 3.8 = 18.24m²
The extra 0.6m (300mm each side) provides overlap for anchoring the liner at the pond edge.
Liner Types
- Butyl rubber (0.75mm): Premium, 20+ year lifespan. £8–12/m²
- EPDM rubber (1.0mm): Very durable, UV resistant. £6–10/m²
- PVC (0.5mm): Budget option, 10–15 year lifespan. £3–6/m²
- HDPE (1.0mm): Rigid, best for formal ponds. £5–8/m²
Don’t Forget the Underlay
Always use a protective underlay beneath the liner to prevent punctures from stones and roots. Geotextile underlay should be the same size as the liner. Budget £2–4/m² extra.
Tips for Irregular Shapes
For kidney-shaped or irregular ponds, measure the maximum length and maximum width at the widest points. Use these as your dimensions in the formula. You will have excess liner to fold at the edges.
Last updated: April 2026