Pond Liner & Water Storage Calculator

Calculate pond liner length and width, liner area, and stored water volume in gallons from pond dimensions, depth, and overlap. Planning estimate only.

Common questions

What size pond liner do I need?
Liner size is pond length and width plus twice the maximum depth in each direction, plus overlap for anchoring in the perimeter trench. This calculator adds all three so you are not short at the anchor trench.
How many gallons will my pond hold?
Volume depends on shape as well as dimensions — a bowl-shaped basin holds far less than the rectangular maximum. The calculator applies a shape factor before converting cubic feet to gallons at 7.48 gal per cubic foot.
Do I need underlayment beneath a pond liner?
On anything but clean sand, yes. Roots, gravel, and stones are the usual cause of punctures, and underlayment or old carpet costs far less than draining a pond to patch it.

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