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Gallons in a Tank Calculator
Calculate how many gallons a rectangular or cylindrical tank holds.
US Gallons
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Liters
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Cubic Feet
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Barrels (42 gal)
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How this was calculated
Rectangular: Volume = L x W x H (in cubic inches), then / 231 = US gallons.
Cylindrical: Volume = pi x (D/2)^2 x Length (cubic inches), then / 231 = US gallons.
1 US gallon = 231 in3 = 3.78541 liters. 1 barrel = 42 US gallons.
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Book a free strategy call →Tank Volume Tips
Knowing your tank capacity in gallons is essential for water storage, fuel management, aquariums, and oilfield production. For oilfield tanks, 1 barrel = 42 US gallons. Standard stock tanks are 210 or 500 barrels. Always account for headspace (typically 10-15% of total volume). Built by Groundwork Analytics.