Pond liner size calculator
Liner sheet needed
Not calculated
Measure the finished excavation. Choose the next stock size up and trim after filling and settling.
Liner method and allowances
length = longest span + (2 × max depth) + (2 × overhang) + fold allowance
width = widest span + (2 × max depth) + (2 × overhang) + fold allowance
Use the longest rim spans at right angles and the maximum depth. The depth allowance covers both walls. An overhang of 12 inches per edge is typical; allow more for large edging or raised walls. Folds use extra material around curves.
Underlay uses the same dimensions. Size streams and waterfalls separately, with overlaps that direct water onto the lower liner.
Use a saved pond trace to compare sheet sizes with and without folds.