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If youâ€™re thinking about adopting a new fish, itâ€™s important to know how many gallons your tank will hold. Most species need a certain amount of space to thrive, so cramming them in a tank thatâ€™s too small can be detrimental to their health. Plus, it helps to know your tankâ€™s size when it comes time to clean the tank. You may even discover that it has a bigger capacity than you realized, which allows you to bring home a couple of new scaly friends. Conversely, maybe youâ€™re starting with a used tank where you know its capacity but are wondering if itâ€™ll fit on your desk. We can help you find out!

The 3 Tips for Calculating Aquarium Volume

1. Determine the shape of your tank.

If you have a simple rectangle, the math is much easier. Other shapes, like a triangular prism, are a bit tricky to calculate, so you might want to rely on a calculator to do the job for you.1

2. Measure your tankâ€™s length, height, and width.

To find the volume of a rectangular tank, youâ€™ll need to measure the tankâ€™s length (the distance from side to side), height (top to bottom), and width (front to back). Multiply all of these measurements together and then divide by 231 gallons. The result is your tankâ€™s capacity in gallons.

3. If you know your tankâ€™s capacity in gallons, you can roughly determine its measurements.

If youâ€™re considering buying a 20-gallon fish tank, but the Craigslist ad doesnâ€™t specify the dimensions, donâ€™t worry. Usually, fish tank sizes are fairly standardized. The obvious exception would be if theyâ€™re unusual shapes, which may have peculiar dimensions. For example, a 20-gallon rectangular tank usually measures 24 x 12 x 16 inches, but a 20-gallon cylindrical tank would have different measurements altogether. You can use this chart to help you get a general idea.

Things to Keep in Mind

Even though a tank may hold a certain number of gallons, you should remember that it never actually will hold that exact amount since you wonâ€™t fill it to the brim. Plus, anything you put in the tank from decorations to pumps to the fish itself takes up space. Itâ€™s important to give your aquatic creatures wiggle room, so always get a tank a little larger than the minimum space requirements.

Conclusion

While talk of volumes and cubic feet may bring back headaches from high school days, you donâ€™t have to be an algebra student to figure out the capacity of your fish tank. Rectangular tanks are easy to figure out yourself, but thankfully, online fish tank calculators provide a way to determine the size of tougher shapes. Once youâ€™ve determined the size or capacity of your tank, you should make sure itâ€™s a little bigger than the minimum requirements to allow your fish to just keep swimming along their merry way.

Featured Image Credit: Wannee_Photographer, Shutterstock

Authored by

Brooke Bundy is a freelance writer who graduated from the University of North Georgia with a B.S. in Media Studies. She is interested in storytelling across different mediums. When she isnâ€™t writing, Brooke loves to spend time with her dog, and three cats, in New Orleans, Louisiana. Brook enjoys gardening cooking, brewing coffee, and making her pet's house a home.

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