Tank Capacity Calculator
The Tank Capacity Calculator computes volume and liquid capacity for rectangular, cylindrical, and conical tanks. Enter your tank shape and dimensions to get instant results in cubic metres, litres, US gallons, and estimated water weight.
Educational estimate. Calculator results are for planning and information only, not financial, tax, medical, legal, or engineering advice. Verify important decisions with official sources or a qualified professional.
Tank Capacity Calculator
Tank Volume & Capacity in Litres & Gallons
📐 Formula & Method
Rectangular Tank
Multiply all three dimensions to get volume in cubic metres.
Cylindrical Tank
Pi times the radius squared times the height.
Conical / Pyramidal Tank Estimate
This option assumes a rectangular-base tapered tank or hopper. For a true circular cone, use Volume = (1/3) × π × (D/2)² × Height.
Unit Conversions
Standard SI and US customary unit conversions.
📋 How to Use
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1
Select the tank shape: Rectangular, Cylindrical, or Conical.
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2
Enter the dimensions — Length and Width for rectangular/conical tanks, Diameter for cylindrical tanks.
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3
Enter the Height (depth) of the tank.
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4
Click "Calculate" to see capacity in m³, litres, gallons, and water weight.
🧮 Worked Examples
Cylindrical tank check
Diameter 1.5 m, height 2 m.
Rectangular tank check
Length 2 m, width 1.5 m, height 1.5 m.
How to Calculate Tank Capacity
Tank capacity is the total volume a container can hold, measured in cubic metres (m³), litres, or gallons. The correct formula depends on the shape of the tank. A rectangular tank uses Length × Width × Height. A cylindrical tank uses π × r² × Height, where r is the radius (half the diameter). A conical tank (pointed bottom) uses ⅓ × base area × height.
To convert m³ to litres, multiply by 1,000. To convert to US gallons, multiply by 264.172. To convert to Imperial (UK) gallons, multiply by 219.969. Water weighs approximately 1 kg per litre at room temperature, so a 1,000-litre tank holds roughly 1,000 kg (1 tonne) of water.
Tank capacity calculations are used in water storage, chemical processing, fuel storage, aquaculture, and construction. Engineers and plumbers use these formulas to size tanks, pumps, and pipelines correctly.
🔬 Methodology & Accuracy
Formula: Uses shape-specific geometric volume formulas, converts m3 to litres using 1 m3 = 1000 L, to US gallons using 1 m3 = 264.172052 US gal, and estimates water mass with density 1000 kg/m3.
Data sources: Standard solid geometry formulas; NIST SI unit relationships for litre and cubic metre; US gallon conversion 1 US gal = 3.785411784 L.
Last reviewed: June 2026 · General formula used: Rectangular Tank · Accuracy: Results are precise to two decimal places using IEEE-754 double-precision arithmetic. Intended for educational and planning use only.
For informational purposes only. Results are estimates based on the inputs and formulas provided. For financial, tax, medical, or legal decisions, consult a qualified professional. Rates and regulations change — always verify current figures with official sources.