Tank Volume Calculator

Water and Chemical Storage Tank Calculator

Not sure what tank size you need? Use our tank calculator to get a quick answer. Simply choose the tank shape you want to find volume for and enter in your dimensions! We have calculators to determine volume for Horizontal Cylinders, Vertical Cylinders, Horizontal Ovals, Vertical Ovals, Horizontal Capsules, Vertical Capsules, Rectangular Tanks, and Spherical Tanks.

Once you have your dimensions and gallon estimate, you can check out our full range of tank options. If you have questions, call us at 863-261-8388 to talk with a team member.


Tank Volume Calculator

Tank Volume Formulas & Calculations

Interested in seeing how the calculator operates under the hood? Click any tank shape below to see the mathematical formulas used in our calculator.

Horizontal Cylinder Tank

For horizontal cylindrical tanks, volume is calculated by multiplying the circular cross-sectional area by the tank length.

Total Tank Volume
$$V = \pi r^2 L$$
  • V = Volume
  • r = Radius (diameter ÷ 2)
  • L = Length of tank
  • π ≈ 3.14159
Partially Filled Volume
$$V_{fill} = L \times r^2 \times (\theta - \sin(\theta))$$

Where:

$$\theta = 2 \times \arccos\left(\frac{r-h}{r}\right)$$
  • h = Height of liquid from bottom
  • θ = Central angle in radians

Vertical Cylinder Tank

Vertical cylinder calculations use the circular base area multiplied by height.

Total Tank Volume
$$V = \pi r^2 H$$
  • H = Total height of tank
  • r = Radius
Partially Filled Volume
$$V_{fill} = \pi r^2 h$$
  • h = Height of liquid

Horizontal Oval (Elliptical) Tank

Oval tanks have a stadium-shaped cross-section (rectangle with semicircular ends).

Total Tank Volume
$$V = L \times (\pi r^2 + 2ra)$$

Where:

  • L = Length of tank
  • r = Height ÷ 2
  • a = Width - Height
  • Width must be greater than height
Note: Partial fill calculations treat this as two half-cylinders connected by a rectangle.

Vertical Oval (Elliptical) Tank

Vertical oval tanks are oriented with the oval cross-section as the base.

Total Tank Volume
$$V = H \times (\pi r^2 + 2ra)$$

Where:

  • H = Height of tank
  • r = Width ÷ 2
  • a = Length - Width
  • Length must be greater than width

Horizontal Capsule Tank

Capsule tanks are cylinders with hemispherical ends.

Total Tank Volume
$$V = \pi r^2 L + \frac{4}{3}\pi r^3$$

This combines:

  • Cylinder volume: πr²L
  • Sphere volume: (4/3)πr³
  • L = Length of cylindrical section
  • r = Radius
Simplified Form
$$V = \pi r^2 \left(L + \frac{4r}{3}\right)$$

Vertical Capsule Tank

Vertical capsules have hemispheres on top and bottom.

Total Tank Volume
$$V = \pi r^2 H + \frac{4}{3}\pi r^3$$
  • H = Height of cylindrical section
  • r = Radius
Partial Fill Considerations

Fill calculations depend on liquid level:

  • If h < r: Only bottom hemisphere filled
  • If r < h < (H+r): Hemisphere + partial cylinder
  • If h > (H+r): Full cylinder + partial top hemisphere

Rectangular Tank

The simplest calculation - multiply length, width, and height.

Total Tank Volume
$$V = L \times W \times H$$
  • L = Length
  • W = Width
  • H = Height
Partially Filled Volume
$$V_{fill} = L \times W \times h$$
  • h = Height of liquid
Example: A 10ft × 8ft × 6ft tank = 480 cubic feet = 3,590 gallons

Spherical Tank

Spherical tanks provide maximum volume with minimum surface area.

Total Tank Volume
$$V = \frac{4}{3}\pi r^3$$
  • r = Radius
  • d = Diameter = 2r
Partially Filled Volume (Spherical Cap)
$$V_{fill} = \frac{\pi h^2}{3}(3r - h)$$
  • h = Height of liquid from bottom

Volume Unit Conversions

Convert calculated volumes to practical units.

Common Conversions
$$\text{1 ft}^3 = 7.48052 \text{ gallons (US)}$$ $$\text{1 ft}^3 = 28.3168 \text{ liters}$$ $$\text{1 gallon} = 231 \text{ in}^3$$ $$\text{1 gallon} = 3.78541 \text{ liters}$$
Quick Reference Table
  • 1 cubic foot = 7.48 gallons
  • 1 cubic meter = 264.17 gallons
  • 1 barrel (oil) = 42 gallons
  • 1 cubic yard = 201.97 gallons

Found your tank size? Contact our dedicated sales team to talk about the product that would best suit your needs.