Pond Liner Size
The liner has to run up both side walls and reach the edge to be anchored, so twice the depth plus an edge overlap is added to both length and width. For a pond that isn't a simple rectangle, cut to the longest length and width and fold the slack at the edges.
Your numbers
Liner length
4.8m
Liner width
3.8m
Liner area
18.24m²
Formula
Liner length = Pond length + 2×Pond depth (m) + 2×Edge overlap (cm)÷100, Liner width = Pond width + 2×Pond depth (m) + 2×Edge overlap (cm)÷100
Add more than 30 cm of margin if you plan to anchor the edge with stones. Seams weaken a liner, so check the size you need can be cut from one uncut sheet.
What to enter
| Input | Default | Accepted range |
|---|---|---|
| Pond length (m) | 3 | 0.3 and up |
| Pond width (m) | 2 | 0.3 and up |
| Pond depth (m) (m) | 0.6 | 0.1 and up |
| Edge overlap (cm) (cm) | 30 | 0 and up |
Step by step
Quick reference table
Results when only Pond length (m) changes and everything else stays put.
| Pond length (m) | Liner length (m) | Liner width (m) | Liner area (m²) |
|---|---|---|---|
| 1.5 | 3.3 | 3.8 | 12.54 |
| 2.25 | 4.05 | 3.8 | 15.39 |
| 3 | 4.8 | 3.8 | 18.24 |
| 4.5 | 6.3 | 3.8 | 23.94 |
| 6 | 7.8 | 3.8 | 29.64 |
What each result means
| Result | At default values |
|---|---|
| Liner length (m)Pond length plus twice the depth plus the edge overlap. | 4.8 |
| Liner width (m) | 3.8 |
| Liner area (m²)Liner length times liner width. | 18.24 |
Common mistakes
Add more than 30 cm of margin if you plan to anchor the edge with stones. Seams weaken a liner, so check the size you need can be cut from one uncut sheet.
Glossary
- Liner length
- Pond length plus twice the depth plus the edge overlap.
- Liner area
- Liner length times liner width.
Frequently asked questions
QHow is Pond Liner Size calculated?
Liner length = Pond length + 2×Pond depth (m) + 2×Edge overlap (cm)÷100, Liner width = Pond width + 2×Pond depth (m) + 2×Edge overlap (cm)÷100 — The liner has to run up both side walls and reach the edge to be anchored, so twice the depth plus an edge overlap is added to both length and width. For a pond that isn't a simple rectangle, cut to the longest length and width and fold the slack at the edges.
QCan you walk through an example?
With Pond length 3m, Pond width 2m, Pond depth (m) 0.6m, Edge overlap (cm) 30cm, the answer is Liner length 4.8m.
QWhat do I need to enter?
Enter Pond length, Pond width, Pond depth (m), Edge overlap (cm). The result recalculates as you type, and an empty box counts as zero.
QHow much does the answer move if I change a number?
Changing only Pond length (m) moves the answer to Pond length (m) 1.5 → Liner length (m) 3.3 and Pond length (m) 6 → Liner length (m) 7.8. The table below lays out five steps.
QHow are the numbers rounded?
Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.
QAnything to watch out for?
Add more than 30 cm of margin if you plan to anchor the edge with stones. Seams weaken a liner, so check the size you need can be cut from one uncut sheet.
Related calculators
Keep your length units consistent across inputs — mixing centimetres and metres throws results far off.