Be sure to jot down your measurements on a scrap piece of paper so you won’t have to try to keep up with them mentally. If the tank you’re measuring is a square, each side will have the same dimensions, so you’ll only need to measure a single side in order to calculate its volume. [2] X Research source The vast majority of fish tanks and aquariums are square or rectangular, so this is the method you’ll want to use if you’re an aquatic wildlife enthusiast.
Depending on the shape of the tank, it may not be easy to tell which side is longer than the other. Just remember that the width and depth will always be perpendicular to one another rather than parallel. In truth, it doesn’t matter what order you measure the sides in, so long as you end up with 3 distinct measurements.
If the tank is resting on another surface and can’t easily be moved, you may need to measure from the supporting surface to the top of the tank. Lay a ruler across the tank’s upper edge and use it to square your tape measure.
If your tank is 36 in. long, 18 in. wide, and 18 in. deep, its volume in cubic inches would be 11,664. Don’t sweat it if you don’t have your device or a standalone calculator handy—you can multiply large numbers on paper or in your head in seconds.
Sticking with the previous example, dividing 11,664 by 231 would give you 50 gallons (or 50. 5, to be precise). If you don’t feel like going to the trouble of crunching all those numbers yourself, pull up a liquid volume calculator online, enter your measurements, and let it do the work for you. [8] X Research source
Most types of storage tanks are manufactured in neat, standardized dimensions, so you shouldn’t have to worry about getting some sort of weird irregular number. The formula you’ll be using will be the same whether your tank is situated upright or horizontally—if it’s on its side, simply substitute the term “length” for “height. ”[10] X Research source Rounded tanks are less common than rectangular ones, but it can still be helpful to know how to measure the volume of one for a school assignment or work-related project.
If your tank measures 16 inches across, it would, therefore, have a radius of 8 inches. In cases where you get an odd diameter, like 16. 25, it’s likely due to the thickness of the walls. If each wall is 0. 125 inches thick, together they would make up one-quarter of an inch. Since this space wouldn’t be reflected in the tank’s volume, it’s safe to round down.
Copy down this number beside your height and radius measurements. You may want to grab a calculator for this step if unpacking mathematical equations on paper isn’t your thing.
Multiplying 64, the squared radius of your tank from the running example, by 3. 1416 gives you 201. In other words, each of the tank’s circular faces has an area of 201 square inches.
Say your tank is 32 inches tall (or long). 201 x 32 = 6,432. That’s a lot of cubic inches!
Do the math: 6,432 ÷ 231 = 27. 8. That’s about 28 gallons. If you live in the UK, don’t forget to go by Imperial gallons rather than U. S. gallons. This would make the conversion value 277. 42 instead of 231. [16] X Research source
