Pond Liner Size Calculator
Free Calculator
Calculate the pond liner size you need
Enter the pond's maximum length, width, and depth, then choose how much overlap you want around each edge. The calculator estimates the minimum rectangular liner and underlayment size.
1. Pond measurements
Extra liner left beyond the pond edge for anchoring and installation.
Minimum liner dimensions
Buy the next available liner size that is at least this large in both dimensions. A little extra is safer than coming up short.
Pond liner formula
Liner length = pond length + (2 × depth) + (2 × overlap)
Liner width = pond width + (2 × depth) + (2 × overlap)
The formula assumes the liner travels down one side, across the deepest portion, and back up the opposite side. Measure the longest, widest, and deepest points rather than averages.
Calculator note
Irregular ponds, deep plant shelves, raised walls, streams, waterfalls, bottom drains, and unusual edge details can require additional material. Treat this as a minimum planning estimate and allow extra liner when the shape is complex.