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Construction
Tank Volume Calculator
Calculate the volume of cylindrical and rectangular tanks in gallons and liters. Includes fill time estimate at common flow rates.

Tank Volume Calculator

Whether you are sizing a water storage tank, estimating rainwater collection capacity, or planning a fish pond, knowing exact tank volume is essential. This calculator handles both cylindrical (round) and rectangular (box) tanks and provides volume in gallons, liters, and cubic feet with a fill time estimate.

For cylindrical tanks, the volume formula is V = π x (diameter/2)² x height. For rectangular tanks, it's simply V = length x width x depth. Results are converted to gallons using the factor of 7.48 gallons per cubic foot.

The fill time estimate helps you plan water delivery or pump sizing. A standard garden hose delivers about 5-10 GPM, while a 1-inch well pump typically delivers 10-15 GPM. Municipal water connections usually provide 15-25 GPM depending on line pressure and pipe size.

For real-world applications, keep in mind that tanks are rarely filled to 100% capacity. Most tank manufacturers recommend leaving 5-10% headspace. Underground tanks also have inlet and outlet fittings that reduce usable volume. For septic tanks and cisterns, consult local building codes for minimum capacity requirements.

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