It needs a 14 × 14 ft liner (196 sq ft), so a 15 × 15 ft standard liner, and holds about 752 gallons. Fold the extra into neat pleats as you fill.
How the pond liner calculator works
PondLinerCalc sizes the liner so it reaches the bottom of the deepest point on both sides and still overlaps the edge: liner length = pond length + 2 × maximum depth + 2 × overlap, and the same for the width. It then rounds each side up to the next 5 ft (or 1.5 m), the steps most EPDM and PVC liners are sold in, and suggests underlayment of the same size. Volume is length × width × average depth, multiplied by π/4 for round or oval ponds, at 7.48 US gallons per cubic foot or 1,000 litres per cubic metre. The pump should turn that volume over once an hour, or twice for koi.
Pond liner sizes for common ponds
Rectangular ponds with a 1 ft overlap each side.
| Pond | Depth | Liner needed | Gallons |
|---|---|---|---|
| 6 × 4 ft | 1.5 ft | 11 × 9 ft | 269 |
| 8 × 6 ft | 2 ft | 14 × 12 ft | 718 |
| 10 × 8 ft | 2 ft | 16 × 14 ft | 1,197 |
| 12 × 10 ft | 3 ft | 20 × 18 ft | 2,693 |
| 15 × 10 ft | 3 ft | 23 × 18 ft | 3,366 |
| 20 × 15 ft | 4 ft | 30 × 25 ft | 8,977 |
Frequently asked questions
What size liner for an 8 ft round pond?
About 14 × 14 ft for a 2 ft deep pond with a 1 ft overlap.
How do I measure an oval pond?
Enter the longest length and widest width; the volume uses the oval (ellipse) area.
Are preformed round ponds better?
Rigid preformed ponds suit small ponds; a liner lets you build any shape and size.
Is PondLinerCalc free?
Yes, with no sign-up or ads, and your pond details stay in your browser.
Should I buy a bit bigger than calculated?
Yes. Measure the dug hole, not the plan, and round up: a liner that is too small cannot be fixed, while extra can be trimmed.