About this calculator
The size of liner to buy for a dug pond, including the depth on both sides and the edge overlap.
How it’s calculated
Liner length = pond length + 2 × max depth + 2 × overlap. Liner width = width + 2 × depth + 2 × overlap.
Worked example
With these inputs:
- Pond length
- 3 m
- Pond width
- 2 m
- Maximum depth
- 0.6 m
- Edge overlap (each side)
- 300 mm
the result is:
- Liner size
- 4.8 m × 3.8 m
- Liner area
- 18.24 m²
Tips from the trade
- Shelves don’t change the liner size. Max depth already covers them.
- Always put a protective underlay beneath the liner.
Results are estimates for planning and pricing. Check quantities against your drawings, the manufacturer’s data and the Building Regulations before ordering.