Turtle Tank Size Calculator

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Calculate the ideal water volume and tank size for aquatic turtles based on shell length and population.

Turtle Profile

Species Preset

Avg Shell Length (inches)

Number of Turtles

Tank Size Comparison

Highlighted bars show standard tanks that can accommodate your setup.

Volume Requirements

40Gallons

Minimum Water Volume

Based on the 10-gallons-per-inch rule + additional residents.

Liters151L

Ideal water temp for most turtles is 75-80°F (24-27°C).

Never use small 'turtle bowls' or half-gallon tanks; they lead to rapid health decline.

About this calculator

The 10-Gallon Rule & Beyond

For aquatic turtles, swimming space is survival space. The gold standard is 10 gallons of water for every 1 inch of shell length. For multiple turtles, the largest turtle needs the full 10g/inch, and each additional turtle requires at least 50% more volume than their individual 10g/inch requirement.

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Pro Tips

Filtration is Key: Turtles produce significantly more waste than fish. Use a filter rated for 2-3x your tank's volume.
Water Depth: The water should be at least 1.5 to 2 times as deep as the turtle's shell is long to allow for easy flipping.
Basking Deck: Every aquatic turtle needs a dry area where they can completely leave the water and dry out their plastron (bottom shell).
Mixing Species: Be cautious! Mixing different turtle species or significantly different sizes can lead to aggression and injury.

Fun Facts

"Turtles are 'semi-aquatic,' meaning they spend a huge chunk of time in water but MUST have dry land for thermoregulation."
"The Red-Eared Slider is the most common pet turtle but can grow up to 12 inches, requiring a massive 120-gallon tank!"
"Turtles have been on Earth for over 200 million years, outliving the dinosaurs."
"Some turtles can hibernate underwater for months by slowing their metabolism to almost zero."