How to Calculate Tank Volume?

October 28, 2025

Accurate volume monitoring helps ensure production safety and efficiency. Generally speaking, the volume of conventional tanks can be calculated using formulas. However, formulas for unusual containers can be more complex. Sino-Inst has launched a volume meter that can calculate the volume of tanks of various shapes. For high-temperature and high-pressure environments, it also features temperature and pressure compensation, providing accurate tank volume.

This article will introduce some common tank volume calculation formulas and Sino-Inst’s volume measurement products. We hope you will find it useful.

What is Tank Volume?

Tank volume refers to the amount of space within a tank that can hold a substance. Depending on the tank’s shape, different calculation formulas can be used to determine its volume.

When filling a tank with liquid, two key figures need to be considered: effective volume and gross volume. The effective volume is the volume a tank can store under normal use. The gross volume refers to the total capacity of all internal spaces within the tank, which includes those not normally filled with liquid. These two figures directly impact the tank’s actual performance and safety factor. The effective volume is typically less than the full volume. This difference is called a safety margin. A safety margin provides a buffer against thermal expansion and contraction of the liquid. For example, traditional chemical storage tank designs require a safety margin of 10%-15% of the total volume. This margin also reduces the effects of liquid sloshing, thereby preventing deformation of the tank structure.

How to calculate tank volume?

Different tank shapes require different calculation formulas. Sino-Inst has compiled the following formulas for calculating the volume of tanks of different shapes:

Horizontal Cylindrical Tanks

To calculate the volume of a horizontal cylinder, we must multiply its base area by its length. If the base area is a circle with radius r, we can calculate its area using πr². Multiplying this by the length gives the total volume of the tank:

V = π × r² × l

Since r = d/2, the above formula can be rewritten as:

V = π × r² × l = π × (d/2)² × l

Vertical Cylindrical Tanks

The total volume formula for a vertical cylinder is the same as for a horizontal cylinder, with the length l replaced by the height h:
V = π × r² × h = π × (d/2)² × h

Rectangular Tank (Rectangular Prism)

This tank shape is often referred to as a “rectangular tank,” but this is not its official name. A rectangle is a 2D shape, while the tank is a rectangular prism. To find the volume of a rectangular prism, we must multiply the tank’s three dimensions—width, length, and height:
V = w × l × h

Horizontal Elliptical Tank

This calculator defines an elliptical tank as a cylindrical tank with a stadium-shaped base. A stadium shape is defined as a rectangle with semicircles at each end. To find the volume of the tank, we must multiply the base area by the length.
Let’s find the base area. The base area is represented by the stadium shape shown in the figure below. The surface area of the stadium shape can be found by adding the surface area of the rectangle and the surface area of the two semicircles. The two semicircles form a circle with a radius of r. Therefore, their total area is πr². The sides of the inner rectangle are a and 2r. Its surface area can be found as 2ar.

The total surface area of the stadium shape can be found as πr² + 2ar. The volume of a horizontal elliptical tank with a stadium-shaped bottom and length l can be found as follows:
V = (πr² + 2ar) × l
Since the calculator works with the height h of the cylinder, and h = 2r, the above formula can be rewritten as:
r = h/2
V = (π(h/2)² + 2a(h/2)) × l = ((πh²)/4 + ah) × l

Vertical elliptical tank

Although the volume of liquid filled in this tank is different from the corresponding volume filled in the horizontal elliptical tank, the overall volume formula is the same:
V = (πr² + 2ar) × l
In this case, w = 2r and r = w/2, so the formula can be rewritten as:
V = (π(w/2)² + 2a(w/2)) × l = ((πw²)/4 + aw) × l
Horizontal capsule-shaped tank

A horizontal capsule-shaped tank is defined as a combination of a cylindrical portion and two hemispherical end caps. We calculate the volume of the horizontal capsule-shaped tank by calculating the volume of the cylinder and the two hemispheres separately. Here is the specific calculation process.

Cylinder Volume:
The center of the capsule is a cylinder. If the radius of the cylinder is r and the side length (the length of the cylindrical portion) is L, the calculation formula of volume is:

Vcylinder = πr²L

Hemispherical End Cap Volume:
Each hemisphere has a radius of r. The volume of a hemisphere is 2/3πr³.
Because there are two hemispheres, their total volume is 2 × 2/3πr³ = 4/3πr³.
The total volume V of the horizontal capsule-shaped tank is equal to the volume of the cylinder plus the sum of the volumes of the two hemispheres:
V = Vcylinder + Vhemisphere = πr²L + 4/3πr³.
Assuming that the radius r is half the diameter d, r = d/2, the formula can be rewritten as:
V = π(d/2)²L + 4/3π(d/2)³.
This formula calculates the volume of a horizontal capsule-shaped tank based on the cylinder diameter and length.

Horizontal Elliptical Tank with 2:1 Semi-Elliptical Head

It has a semi-elliptical head, where the width of the ellipse is twice its depth. Let a be the line length and the tank depth (H) be a/4. Therefore, the total volume of the tank can be calculated using the following formula: Vₕ = πHd²/3
The volume of the cylinder can be calculated as follows:
V꜀ = (π × d² × a)/4
The total tank volume is:
V = Vₕ + V꜀

Vertical Capsule Tank

Although the volume of liquid in this tank is different from the corresponding volume in a horizontal capsule tank, the total volume formula is the same. You can refer to:
V = πr² × ((4/3)r + a) = π × (d/2)² × ((4d/6) + a)

How to Measure Tank Volume?

Using formulas for every volume calculation is cumbersome. Sino-Inst has launched a tank volume meter. A tank volume meter is an intelligent instrument used in industrial settings. It collects liquid level data and, combined with the tank’s geometric parameters, converts the liquid level into a corresponding volume. It is right for accurate volume measurement and monitoring of both regular and irregular tanks.

Core Function

Utilizes a lookup table or mathematical calculations. Accurate conversion of liquid level to volume is achieved by combining tank geometry parameters, such as horizontal, spherical, and vertical tanks.
Compatible with various liquid level sensors (such as radar, ultrasonic, and submersible).
Alarm and control functions include 2-4 limit alarms (such as upper/lower limit, upper/lower limit), which can trigger valve or pump start/stop.
Multi-signal compatibility: It has various input signals. Data exchange integrates RS-485/RS-232 communication interfaces and supports MODBUS RTU protocol. It can connect with PLCs or computers to process data.
Select models support RS-232C printing for manual or scheduled report output.

Technical Parameters:

High precision and interference resistance;
High-definition color liquid crystal display;
Measurement accuracy reaches 0.2%;
Optoelectronic isolation technology is used between input/output/power supply/communication;
Enhanced electromagnetic interference resistance;
Flexible configuration supports analog output (e.g., 4-20mA);
Provides a DC24V power supply for field transmitters for data security;
Parameter settings are password-protected;
Permanently saves data after a power failure;
Supports factory reset;
Handles complex tank conditions (e.g., tilt, radial deviation).

Applications

Tank gauging
Environmental monitoring
Hazardous materials management
Inventory management of petroleum storage tanks and chemical raw material tanks.
Real-time monitoring of liquid level-volume changes in sewage treatment tanks to optimize reagent dosage.
Linked audible and visual alarm systems prevent leaks in liquefied gas storage tanks and slurry tanks.

Sino-Inst Featured Level Meter

Common Volume Units and Units Conversion

The volume unit conversion table helps you quickly convert values between different volume units. Below are some common volume units and their conversion relationships, especially with milliliters (ml):

1 cubic meter (m³) = 1000 cubic centimeters (cm³)
1 cubic centimeter (cm³) = 1000 cubic millimeters (mm³)
1 liter (L) = 1000 milliliters (mL)
1 US gallon (gal) = 3.78541 liters (L)
1 Imperial gallon (gal) = 4.54609 liters (L)
1 cubic foot (ft³) = 0.0283168 cubic meters (m³)

How to calculate volume in liters?

We can calculate the corresponding volume using the above formula. Then, using the relevant units, we can convert to obtain the tank volume in liters.
The easiest way is to use our volume meter. The instrument automatically measures and converts the data you need.

How to figure out how many gallons are in a tank?

We can use two measurement methods: direct observation and indirect calculation.
If the tank has a level gauge or level indicator, you can directly check the remaining tank capacity.
Alternatively, we can install a level gauge on the tank and use it with our volume recorder. We can then directly check the remaining tank capacity on the volume recorder.

How do you calculate the volume of a tank?

Different tank shapes have different volume calculation formulas, which we've detailed above. You can also use a volume meter to automatically calculate and display the tank volume.

Sino-inst is a Chinese supplier of volume meters. Our volume meters can be used with various level meters and can be used on various tanks.

If you need to purchase a volume meter, please feel free to contact us for a quote. Sino-Inst can provide you with a free volume measurement solution. If you’re still struggling with volume calculations, our volume meters can eliminate your worries. Our products come with a one-year warranty. We can also provide you with a free technical guide.