What Size Pond Liner Do I Need? Liner Size Chart
Part of the project planner: Planning pools, ponds and water storage.
A pond 10 ft long, 8 ft wide and 2 ft deep needs a liner 16 ft by 14 ft (224 square feet). The sum is the pond length, plus twice the depth, plus the overlap on both ends, and the same for the width. The liner goes down one side, across the bottom and up the other, with a foot or so left on the bank. The pond liner calculator does it for your own pond.
Liner size for common ponds
With a 1 ft overlap on each edge, using the longest length, the widest width and the greatest depth:
| Pond | Depth | Liner size | Area | Next common roll size |
|---|---|---|---|---|
| 6 × 4 ft | 1.5 ft | 11 × 9 ft | 99 ft² | 10 × 12 ft |
| 8 × 6 ft | 2 ft | 14 × 12 ft | 168 ft² | 12 × 15 ft |
| 10 × 8 ft | 2 ft | 16 × 14 ft | 224 ft² | 15 × 20 ft |
| 12 × 8 ft | 2 ft | 18 × 14 ft | 252 ft² | 15 × 20 ft |
| 12 × 10 ft | 2.5 ft | 19 × 17 ft | 323 ft² | 20 × 20 ft |
| 15 × 10 ft | 2.5 ft | 22 × 17 ft | 374 ft² | 20 × 25 ft |
| 20 × 15 ft | 3 ft | 28 × 23 ft | 644 ft² | 25 × 30 ft |
| 25 × 20 ft | 3 ft | 33 × 28 ft | 924 ft² | 30 × 40 ft |
How depth changes the size
For a 10 × 8 ft pond with a 1 ft overlap, each extra foot of depth adds 2 ft to the length and the width:
| Depth | Liner size | Area |
|---|---|---|
| 1 ft | 14 × 12 ft | 168 ft² |
| 1.5 ft | 15 × 13 ft | 195 ft² |
| 2 ft | 16 × 14 ft | 224 ft² |
| 2.5 ft | 17 × 15 ft | 255 ft² |
| 3 ft | 18 × 16 ft | 288 ft² |
| 4 ft | 20 × 18 ft | 360 ft² |
How overlap changes the size
| Overlap on each edge | Liner size | Area |
|---|---|---|
| 0 ft | 14 × 12 ft | 168 ft² |
| 1 ft | 16 × 14 ft | 224 ft² |
| 1.5 ft | 17 × 15 ft | 255 ft² |
| 2 ft | 18 × 16 ft | 288 ft² |
Measuring an irregular pond
- Use the longest length, the widest width and the greatest depth, wherever they are. A curved pond uses the same box size as a rectangle that holds it.
- Add a foot to the length and the width for every shelf or step, since the liner follows each level and each wall.
- Measure the depth from the top edge of the pond to the deepest point, since the liner has to go up the sides to the top.
- If in doubt, go up a size: a liner that is too small cannot be fixed, but extra liner can be trimmed.
Choosing the liner and laying it
- Materials. EPDM rubber is flexible, lasts for decades and is the usual choice for garden ponds. PVC is cheaper but less flexible and weaker in sunlight. Reinforced polyethylene is light and strong. Ask for liner that is safe for fish.
- Underlayment. Lay a protective layer on a smooth, stone-free base, then the liner.
- Laying it. Warm the liner in the sun so that it is flexible, lay it loosely, and fill the pond slowly while you smooth the folds.
- Trim last. Cut the extra liner only after the pond has filled and settled, and hide the edge under rocks or coping.
- Check the rules. Some towns treat a pond deeper than about two feet like a pool and require a fence. Check with your building department.
Need the volume for the pump and the fish? Use the pond volume calculator. For the soil you dig out, see the excavation calculator. A 6 × 4 ft pond needs only 11 × 9 ft, so a small pond is a good first project.
Frequently asked questions
How do I work out what size pond liner I need?
Add the pond's length, twice its greatest depth and the overlap you want on both ends, and do the same for the width. A 10 × 8 ft pond 2 ft deep with a 1 ft overlap needs 16 × 14 ft.
How much overlap should a pond liner have?
A foot at each edge is the usual minimum, which adds 2 ft to the length and the width. Use more if the liner will be folded under coping or rocks.
What size liner for a small pond?
A pond 6 ft long, 4 ft wide and 1½ ft deep needs 11 × 9 ft, and the next common roll size is 10 × 12 ft.
Do I need to add extra liner for shelves?
Yes. Shelves and steps make the liner follow more surface, so add about a foot to the length and the width for each level.
Do I need underlayment under a pond liner?
It is a good idea. Underlayment (or damp sand or old carpet) protects the liner from roots and stones. Buy about the same area as the liner.
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Estimates only. Quantities depend on your materials, site and supplier. Confirm important numbers before you order, and follow local building codes for anything structural.