Tank Volume Calculator

Rectangular Tank Volume Calculator

Calculate the volume of liquid in rectangular, square, and cuboid tanks. Perfect for aquariums, water storage, and industrial applications with simple, accurate calculations.

Rectangular Tank Volume Calculator
Calculate the volume of liquid in rectangular, square, and cuboid tanks using the simple formula V = L × W × H

Tank Diagram

Length (L)Width (W)Height (H)Liquid

Measurement Tips:

  • Always measure internal dimensions
  • Length is typically the longest horizontal dimension
  • Width is the shorter horizontal dimension
  • Height is measured vertically from bottom to top
  • Liquid height is measured from the tank bottom

What is a Rectangular Tank?

A rectangular tank, also known as a cuboid or box-shaped tank, has six flat faces with opposite faces being parallel and equal. These tanks are characterized by their straight edges and right angles, making them the simplest tanks to calculate volume for and manufacture.

Aquariums
Fish tanks and marine displays
  • • Home aquariums
  • • Commercial fish displays
  • • Breeding tanks
  • • Quarantine systems
Water Storage
Residential and commercial water systems
  • • Rainwater collection
  • • Emergency water storage
  • • Irrigation reservoirs
  • • Fire suppression systems
Industrial Use
Manufacturing and processing applications
  • • Chemical processing
  • • Food production
  • • Wastewater treatment
  • • Custom installations

Advantages of Rectangular Tanks

Design Benefits

  • • Simple, straightforward geometry
  • • Easy to manufacture and install
  • • Efficient use of space
  • • Stackable and modular designs

Practical Benefits

  • • Easy volume calculations
  • • Simple to clean and maintain
  • • Cost-effective construction
  • • Versatile sizing options

How to Use the Calculator

1

Choose Units

Select your preferred measurement units (feet, inches, meters, etc.)

2

Measure Dimensions

Enter the length, width, and total height of your tank

3

Enter Liquid Height

Input the current height of liquid from the bottom of the tank

4

Get Results

View calculated volumes in gallons, liters, and other units

Formula Used

Rectangular Tank Volume Formula
The simplest volume calculation in geometry

Total Volume:

V = L × W × H

Liquid Volume:

Vliquid = L × W × Hliquid

L = Length

Longest horizontal dimension

W = Width

Shorter horizontal dimension

H = Height

Vertical dimension

Note: This formula works for any rectangular prism, including cubes (where L = W = H) and long rectangular tanks. Always use internal dimensions for accurate liquid volume calculations.

Worked Examples

Example 1: Home Aquarium
Standard 75-gallon aquarium calculation

Given Dimensions:

  • Length: 48 inches
  • Width: 18 inches
  • Height: 21 inches
  • Water level: 19 inches (allowing for air space)

Calculation:

V = 48 × 18 × 19 = 16,416 cubic inches

Converting to gallons: 16,416 ÷ 231 = 71.1 gallons

Result: This aquarium holds approximately 71 gallons of water, which matches the standard 75-gallon rating when accounting for glass thickness and decorations.

Example 2: Water Storage Tank
Rectangular rainwater collection system

Given Dimensions:

  • Length: 8 feet
  • Width: 4 feet
  • Height: 6 feet
  • Current water level: 4.5 feet

Calculation:

V = 8 × 4 × 4.5 = 144 cubic feet

Converting to gallons: 144 × 7.48 = 1,077 gallons

Result: The tank currently contains 1,077 gallons of water, with a total capacity of 1,436 gallons when full.

Example 3: Industrial Process Tank
Chemical storage and mixing vessel

Given Dimensions:

  • Length: 3 meters
  • Width: 2 meters
  • Height: 2.5 meters
  • Liquid level: 1.8 meters

Calculation:

V = 3 × 2 × 1.8 = 10.8 cubic meters

Converting to liters: 10.8 × 1,000 = 10,800 liters

Result: The tank contains 10,800 liters (2,853 gallons) of liquid, operating at 72% capacity.

Frequently Asked Questions - Rectangular Tanks