How to Calculate the Volume of Water to Fill a Rectangular Tank

How to Calculate the Volume of Water to Fill a Rectangular Tank
••• Eak8dda/iStock/GettyImages

When it comes time to fill a rectangular tank, whether it’s an aquarium or a swimming pool, the number of gallons the task may seem mysterious. That’s probably because many people don’t have a very good sense of how much space a gallon takes up. Calculate how much water (or any other liquid) a tank can hold by measuring the tank's volume and convert that figure to gallons.

    Measure the length, width, and depth of the interior of the tank in feet and inches. Convert the dimensions to decimal feet by dividing the number of inches by twelve and adding to the number of feet. For example, 7 feet 9 inches is 7.75 feet.

    Calculate the tank’s volume in cubic feet. The product of the length, width and depth equals volume. For example, 7.75 feet long by 4.5 feet wide by 3 feet deep would be 7.75x4.5x3 = 104.625 cubic feet.

    Convert the volume in cubic feet to the capacity in gallons. Multiply the tank’s volume by 7.48, the number of gallons in a cubic foot. For example, 104.625x7.48 = 782.6 gallons.

    Things You'll Need

    • Tape measure
    • Calculator (optional)

Related Articles

How to Convert Inches to Gallons for an Oil Tank
How to Convert Cubic Feet to Gallons
How to Calculate the Volume of Water in a Square Tank
How to Determine Square Feet Area
How to Calculate Gallons and Tank Volume
How to Find the Volume of a Sphere in Terms of Pi
How to Calculate the Horsepower of a Compressor
How to Find the Height of a Rectangular Pyramid
How to Use Water Displacement to Calculate Volume
How to Calculate CFM to MPH
How to Calculate Water Volume in a Round Container
How to Calculate Perimeter and Area Ratio
How to Calculate Area From Width & Length
How to Calculate Liters
How to Figure the Cubic Yards in a Circle
How to Write Number Measurement Dimensions
How to Calculate a Circular Area
How to Convert Inches to Gallons for an Oil Tank
How to Calculate Hydraulic Cylinder Tonnage
How to Find the Area of Squares