📦 Rectangular Shaped Cistern Capacity Calculator|Cistern Capacity Calculator

Calculate water tank capacity in gallons, liters, cubic feet, and cubic meters

📏 Tank Dimensions

💡 How to Use This Rectangular Tank Volume Calculator

This calculator helps you determine the exact capacity of any rectangular tank, whether it's a water storage tank, aquarium, fuel tank, or swimming pool. Simply follow these steps:

  • Step 1: Enter the length, width, and height of your tank.
  • Step 2: Select your measurement unit (Feet, Meters, Centimeters, or Inches).
  • Step 3: Optionally set the fill level percentage to calculate partial volume.
  • Step 4: Click "Calculate Tank Volume" to see results in multiple units.

The calculator instantly converts between cubic feet, cubic meters, US gallons, and liters — no manual conversions needed!

📐 Rectangular Tank Volume Formula

The volume of a rectangular tank is calculated using the simple formula:

V = L × W × H

Where:

  • V = Volume of the tank
  • L = Length of the tank
  • W = Width of the tank
  • H = Height of the tank

Once you have the volume in cubic units, use these conversion factors:

FromToMultiply By
Cubic Feet (ft³)US Gallons7.48052
Cubic Feet (ft³)Liters28.3168
Cubic Meters (m³)US Gallons264.172
Cubic Meters (m³)Liters1000
Cubic Inches (in³)US Gallons0.004329
Cubic Centimeters (cm³)Liters0.001

🏠 Common Applications

💧 Water Storage Tanks

Calculate the capacity of residential or commercial water storage tanks. A typical household of 4 people uses 300-400 gallons per day. Use this calculator to size your cistern or water tank appropriately.

🐠 Aquariums & Fish Tanks

Determine the exact water volume for your aquarium to properly dose medications, conditioners, and select appropriate filters and heaters.

⛽ Fuel & Oil Tanks

Calculate storage capacity for diesel, gasoline, or oil tanks. Knowing the exact volume helps with inventory management and regulatory compliance.

🏊 Swimming Pools

Estimate pool water volume for chemical treatment, heating requirements, and water filling costs.

🌾 Agriculture & Farming

Size water tanks for livestock, irrigation systems, and crop spraying equipment.

📏 Tank Sizing Guide

Here are common rectangular tank sizes and their approximate capacities:

Dimensions (ft)Volume (ft³)GallonsLiters
3 × 2 × 21290340
4 × 3 × 224180680
5 × 4 × 3604491,699
6 × 4 × 3725392,039
8 × 6 × 41921,4365,435
10 × 8 × 54002,99211,327
12 × 10 × 67205,38620,388

❓ Frequently Asked Questions

How do you calculate the volume of a rectangular tank?
The volume of a rectangular tank is calculated using the formula: Volume = Length × Width × Height. For example, a tank that is 6 ft long, 4 ft wide, and 3 ft high has a volume of 72 cubic feet.
How many gallons is my rectangular tank?
Multiply the cubic feet volume by 7.48052 to get US gallons. For metric: cubic meters × 264.172 = gallons, or liters ÷ 3.78541 = gallons.
What is the formula for tank capacity in liters?
For dimensions in meters: Length × Width × Height × 1000 = Liters. For dimensions in centimeters: (L × W × H) ÷ 1000 = Liters. For dimensions in feet: cubic feet × 28.3168 = Liters.
How do I calculate partial fill volume?
Use the fill level percentage. For example, if your tank holds 500 gallons at 100% full, at 60% fill it holds 300 gallons. This calculator automatically computes partial fill volume.
What's the difference between US gallons and Imperial gallons?
This calculator uses US gallons (1 US gal = 3.78541 liters). Imperial gallons (UK) are larger: 1 Imperial gal = 4.54609 liters. Multiply US gallons by 0.832674 to get Imperial gallons.
How much does the water weigh?
Water weighs approximately 8.34 pounds per US gallon or 1 kilogram per liter. This calculator shows the total water weight at full capacity to help with structural load calculations.