Tank Volume Calculator

Whether you are managing industrial storage or a home water system, our comprehensive tank capacity calculator easily determines the total volume of your tank and the exact volume of liquid it currently holds. This makes it an essential tool for accurately measuring partially filled tanks. Fast, precise, and easy to use, our tank volume calculator supports a wide variety of standard tank shapes, including:

• Horizontal cylinder
• Vertical cylinder
• Rectangular prism
• Horizontal oval tank
• Vertical oval tank
• Horizontal capsule tank
• Vertical capsule tank
• Horizontal semi-elliptical tank with 2:1 semi-elliptical tank heads
• Horizontal tank with dish heads

For ultimate convenience, your results are instantly calculated and displayed across multiple standard metrics, including U.S. gallons, imperial gallons, liters, cubic meters, and cubic feet.

How to Use the Tank Volume Calculator

Using our liquid volume calculator is fast and straightforward. First, select your specific tank shape from the drop-down menu. Next, input your known measurements into the corresponding fields—each shape requires specific dimensions. If your tank is not completely full, simply enter the current filled depth. (Note: The filled depth is the only optional metric; all other dimensional values are required.) Once your data is entered, click "Calculate."

The tool will instantly compute both the total maximum tank capacity and the exact liquid volume currently stored inside.

Input formatting: This calculator accepts integers, decimals, fractions, and numbers in scientific (e) notation. Please ensure that all inputs representing physical dimensions are greater than zero. The optional filled depth, however, must be greater than or equal to zero.

Calculating Tank Capacity: Formulas and Methods

Understanding how to calculate the total volume of a tank is essential for proper storage management and inventory control. Below, we break down the specific mathematical formulas used to determine tank capacity. The dimension symbols referenced in these formulas correspond directly to the diagrams provided for each respective tank shape.

Horizontal cylinder tank

To find the volume of a horizontal cylindrical tank, you must multiply the area of its circular base by its total length. If the circular base has a radius of r, its area is expressed as πr². Multiplying this base area by the tank's length (l) yields the total volume:

V = π × r² × l

Because the radius (r) is exactly half of the diameter (d/2), we can easily rewrite this formula to use the diameter instead:

V = π × r² × l = π × (d/2)² × l

Vertical cylinder tank

The formula used to calculate the volume of a vertical cylinder is almost identical to that of its horizontal counterpart. The only difference is that the length (l) is replaced by the tank's height (h):

V = π × r² × h = π × (d/2)² × h

Rectangular tank (rectangular prism)

While commonly referred to as a "rectangular tank," the geometrically accurate term for this 3D structure is a rectangular prism (since a standard rectangle is merely two-dimensional). To find the volume of a rectangular prism tank, simply multiply its three core dimensions: width (w), length (l), and height (h):

V = w × l × h

Horizontal oval tank

For the purposes of our calculator, an oval tank is defined as a cylinder with a "stadium-shaped" base. A stadium shape consists of a central rectangle capped by semicircles on opposite ends. To determine the overall tank volume, we first need to calculate the base area and then multiply it by the tank's length.

Let's break down the base area calculation. As shown in the diagram below, the stadium shape's total area is the sum of the central rectangle's area and the area of the two semicircles. Together, the two semicircles form one complete circle with a radius of r, giving them a combined area of πr². The central inner rectangle has a length of a and a width of 2r, making its surface area 2ar.

Consequently, the total surface area of the stadium-shaped base is expressed as πr² + 2ar.

To find the volume of a horizontal oval tank with a stadium-shaped base and a length of l, we use this equation:

V = (πr² + 2ar) × l

Because our calculator operates using the total height of the cylinder (h), where h = 2r, we can substitute the radius variables to rewrite the formula as follows:

r = h/2

V = (π(h/2)² + 2a(h/2)) × l = ((πh²)/4 + ah) × l

Vertical oval tank

Although calculating the partially filled liquid volume for a vertical oval tank differs from the horizontal calculation, the formula for determining the total tank volume remains exactly the same:

V = (πr² + 2ar) × l

For a vertical orientation, the width (w) is equal to 2r, meaning r = w/2. Therefore, we can adapt the formula to rely on width instead of radius:

V = (π(w/2)² + 2a(w/2)) × l = ((πw²)/4 + aw) × l

Horizontal Capsule Tank

A horizontal capsule tank consists of a central cylindrical section capped by two hemispherical ends. To determine the total capacity, we must add the volume of the cylinder to the combined volume of these two hemispheres.

• Cylinder Volume: The central body of the capsule is a cylinder. If this cylinder has a radius r and a side length (cylindrical section length) L, its volume is calculated as:

$$V_{cylinder} = \pi r^2 L$$

• Hemispherical End Caps Volume: Both end caps are hemispheres with a radius r. The formula for the volume of a single hemisphere is:

$$\frac{2}{3}\pi r^3$$

Because there are two identical hemispheres, their combined volume equals the volume of a full sphere:

$$2 \times \frac{2}{3}\pi r^3 = \frac{4}{3}\pi r^3$$

Therefore, the total volume V of the horizontal capsule tank is simply the sum of the cylinder and the two hemispherical ends:

$$V = V_{cylinder} + V_{hemispheres} = \pi r^2 L + \frac{4}{3}\pi r^3$$

Since the radius r is exactly half of the diameter d (i.e.,

$$r = \frac{d}{2}$$

), we can rewrite the total volume formula using the tank's diameter:

$$V = \pi \left( \frac{d}{2} \right)^2 L + \frac{4}{3}\pi \left( \frac{d}{2} \right)^3$$

This equation provides a highly accurate volume calculation for a horizontal capsule tank using only its diameter and the length of its straight cylindrical section.

Vertical capsule tank

Similar to oval tanks, calculating the volume of liquid in a partially filled vertical capsule tank differs from the horizontal calculation. However, the formula for the total maximum volume of the tank remains unchanged:

V = πr² × ((4/3)r + a) = π × (d/2)² × ((4d/6) + a)

Horizontal elliptical tank with 2:1 semi-elliptical tank heads

This specific style of tank features semi-elliptical ends where the width of the ellipse is exactly twice its depth. Let's assume the straight cylindrical length is a. If we denote the depth of the head as H, its value will be d/4. With these parameters in mind, the total volume of the semi-elliptical tank heads is calculated as follows:

Vₕ = πHd²/3

Next, the volume of the central cylindrical body is calculated using:

V꜀ = (π × d² × a)/4

Finally, the total capacity of the tank is simply the sum of the volume of the heads and the cylinder:

V = Vₕ + V꜀

Horizontal tank with dish ends

Our tank size calculator is fully equipped to compute both the total capacity and the partially filled liquid volume for horizontal tanks featuring dish ends (also known as dished heads). Because the underlying mathematical formulas for this specific shape are highly complex and extensive, we have omitted the manual calculations here—rest assured, the calculator handles all the heavy lifting for you!

Real-World Calculation Example

Imagine you are managing an oil tank with a horizontal oval shape. It has a height of 3 meters, a width of 4 meters, and a length of 6 meters. According to safety guidelines, this tank cannot be filled beyond 90% of its total volume.

You need to determine: What is the total volume of the tank? Furthermore, if you fill the tank to a depth of 2.5 meters, will you remain within the 90% safety threshold?

Let's use our liquid volume calculator to find the answers! First, select "Horizontal Oval" from the shape drop-down menu. Then, enter your known dimensions:

• h = 3
• w = 4
• l = 6
• f = 2.5

After clicking "Calculate," the tool instantly reveals that the total tank volume is approximately 60.4115 cubic meters (or 15,959.03 U.S. gallons). It also calculates the filled volume at a 2.5-meter depth, showing a total fullness of 87.3%. Since 87.3% is well under the 90% maximum limit, you can confidently conclude that filling the tank to this depth keeps you safely within operational bounds.