The Pond Calculator estimates how much water your pond holds and how much liner material you'll need to build it. Select your pond shape (rectangular, circular, or triangular), then enter the dimensions, average depth, and liner overlap to get your pond volume, surface area, and full liner dimensions including total liner area.
Pond Volume
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Pond Surface Area
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Liner Length Required
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Liner Width Required
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Total Liner Area
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Pond volume depends on shape and average depth. For rectangular ponds: length × width × average depth × 7.48 (gallons per cubic foot). For circular ponds: π × radius² × average depth × 7.48. Always use average depth rather than maximum depth for more accurate calculations.
Calculate liner dimensions by adding twice the maximum depth plus overlap to each pond dimension. For a 10×6 ft pond with 3 ft depth and 1 ft overlap: liner length = 10 + 2×(3+1) = 18 ft, liner width = 6 + 2×(3+1) = 14 ft.
Plan for 1-2 feet of liner overlap beyond the pond edges. This overlap allows proper anchoring, accounts for ground settling, and provides material for finishing edges with rocks or other decorative elements.
Pond depth depends on your goals. For fish ponds, minimum 2-3 feet prevents freezing. Koi ponds should be 4-6 feet deep. Water gardens can be shallower at 1-2 feet. Consider local climate and intended fish species.
Always use average depth for volume calculations. Average depth is typically 60-70% of maximum depth for most pond designs. Using maximum depth will significantly overestimate the actual water volume.
For basic circulation, pump capacity should turn over the entire pond volume every 2-4 hours. For ponds with fish, aim for complete turnover every 1-2 hours. Consider head height and pipe length when selecting pump size.