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Enter the number of tortoises and the shell length in inches, measured straight from the front to the back of the shell. The calculator applies the widely used planning rule of 10 times the shell length for enclosure length and 5 times for width, then gives the area per tortoise and the total area for the group. This is a minimum-size planning rule for indoor or outdoor housing, not veterinary advice: larger is almost always better for tortoises.
Tortoise enclosure size scales with the animal, not with a fixed tank size. The planning rule used here is: enclosure length = shell length × 10, and enclosure width = shell length × 5. Area per tortoise = length × width, and total enclosure area = area per tortoise × number of tortoises.
Worked example: a tortoise with an 8 inch shell needs an enclosure 80 inches long (6.67 ft) and 40 inches wide (3.33 ft), which is 22.22 sq ft. Two tortoises with 6 inch shells need 5 ft by 2.5 ft each, 12.5 sq ft per tortoise and 25 sq ft in total. Measure shell length in a straight line, not over the curve of the shell, or the enclosure will come out too small.
Enter the number of tortoises that will share the enclosure. Enter the shell length in inches of the largest tortoise in the group, so the enclosure suits every animal in it. Press Calculate to see the enclosure length, width, area per tortoise, and total enclosure area in square feet.
Use the result as a minimum, then build bigger if you have room: tortoises walk, graze, bask, and dig, and a cramped enclosure shows up quickly as pacing, shell damage, and stress. Check the enclosure dimensions against the species table before you buy materials, since a long narrow shape can meet the area target while leaving too little turning room. If you keep tortoises of very different sizes, size the enclosure for the largest animal and give smaller ones their own hides and feeding spots.
Shell length varies hugely by species, so the same rule gives very different enclosures:
| Species | Typical adult shell length | Minimum enclosure (one tortoise) | |---|---|---| | Hermann's tortoise | 6-8 in | 5.00 × 2.50 ft to 6.67 × 3.33 ft | | Russian (Horsfield's) tortoise | 6-10 in | 5.00 × 2.50 ft to 8.33 × 4.17 ft | | Red-footed tortoise | 10-14 in | 8.33 × 4.17 ft to 11.67 × 5.83 ft | | Leopard tortoise | 10-18 in | 8.33 × 4.17 ft to 15.00 × 7.50 ft | | Sulcata tortoise | 24-30 in | 20.00 × 10.00 ft by the length rule; 600+ sq ft outdoors recommended |
Sulcata tortoises outgrow indoor housing: an adult sulcata needs a large secure outdoor enclosure with a heated shelter, not a tortoise table. Note that several keeper guides also set a practical floor of 8 ft by 4 ft (32 sq ft) for even the smallest adult outdoors, which is larger than the length rule gives for a 6 inch tortoise, so treat the calculator result as a minimum and build to the larger figure when the two differ. A tortoise enclosure for 1 tortoise of a small species can be a tortoise table indoors, while a tortoise enclosure for 2 tortoises should add a second hide, a second basking spot, and separate feeding areas to reduce competition.
An indoor tortoise enclosure, often called a tortoise table, is an open-topped wooden enclosure that gives better airflow than a glass vivarium. Glass tanks trap humidity, stress tortoises that do not understand glass, and are almost always too small for an adult. A tortoise table sized by this calculator, with solid sides the tortoise cannot see through, works far better.
How big a tortoise table should be depends on the species table above: a baby tortoise can start small, but it will need the adult-size enclosure within a few years, so building the adult size first saves a rebuild. A tortoise enclosure for a baby tortoise still needs a warm basking end, a cooler end, a hide, a water dish, and room to walk between them: a tiny box with no temperature gradient is not a home, even for a hatchling.
Can tortoises live outside? Most temperate species can live outside for at least part of the year if the enclosure is secure, sunny, and well drained, and if they have a heated, insulated shelter for cold nights. An outdoor enclosure should be larger than the indoor minimum, with grazing plants, a basking area, hides, and a shallow water dish the tortoise can climb into and out of.
Outdoor fencing must be sunk into the ground, because tortoises dig, and tall enough that they cannot climb out over it. Netting or a lid protects against birds of prey, rats, and dogs. In cold climates, tortoises that hibernate need a safe, frost-free hibernation setup, and tropical species such as red-footed tortoises must come indoors when temperatures fall.
Tortoise enclosure heating creates the temperature gradient tortoises need to regulate their body heat. Provide a basking spot of about 30 to 35 degrees C under a heat lamp, with a cooler end around 20 to 25 degrees C, plus UVB light for shell and bone health. Night temperatures can fall to room temperature for most temperate species, but tropical species need warmer nights.
Tortoise enclosure substrate should hold burrows and allow digging: a mix of topsoil and play sand works well for many species, while red-footed and other forest species prefer a more humid mix with coconut fibre. Avoid tiny gravel and wood chips that can be eaten, and keep the substrate dry enough to prevent shell rot but humid enough for the species. Always include a hide at each end, a cuttlebone for calcium, and a water dish large enough to soak in.
Tortoises are not social in the way dogs are, and crowding causes problems. As a rule, one male per enclosure is safest, because males fight and harass females, especially in breeding season. Females can often live together if the enclosure is large, with multiple hides, basking spots, and feeding stations so no one animal guards all the resources.
This calculator multiplies the area per tortoise by the group size, which is the right starting point, but for a group you should add extra space beyond the bare total, and watch for bullying in the first weeks. Signs of trouble include one tortoise constantly hiding, bite marks on legs or shell edges, and one animal eating far less than the rest. If that happens, separate the animals: a bigger enclosure rarely fixes a bullying problem on its own.
Use 10 times the shell length for length and 5 times for width. An 8 inch tortoise needs 6.67 ft by 3.33 ft, or 22.22 sq ft. Larger species need far more: a 30 inch sulcata needs 25 ft by 12.5 ft outdoors.
Space scales with shell length. A small Hermann's or Russian tortoise needs roughly 12.5 to 22 sq ft, a red-footed tortoise needs roughly 35 to 68 sq ft, and an adult sulcata needs 200 sq ft or more. These are minimums; bigger is better.
The widely used minimum is 10 times shell length by 5 times shell length per tortoise. Anything smaller restricts walking, basking, and temperature choice, and it is not a long-term home even for a baby tortoise.
Size the table by the adult shell length using this calculator. A table for an 8 inch tortoise should be at least 6.67 ft by 3.33 ft. Tables are better than glass vivariums because they give airflow and the tortoise cannot see through solid sides.
A closed glass vivarium is usually too small and too humid for an adult tortoise, and tortoises stress against glass they cannot pass. An open-topped tortoise table or a secure outdoor enclosure is almost always the better choice.
Yes, temperate species can live outside in a secure, sunny, well-drained enclosure with a heated shelter for cold nights, and tropical species need to come indoors when temperatures fall. Outdoor fencing must be sunk into the ground because tortoises dig.
Provide a basking spot of about 30 to 35 degrees C and a cooler end of about 20 to 25 degrees C, with UVB light, so the tortoise can choose its temperature. Night temperatures can fall to room temperature for temperate species.
A topsoil and play sand mix suits many species and allows digging. Forest species such as red-footed tortoises prefer a more humid coconut fibre mix. Avoid small gravel and wood chips that can be eaten.
Keep one male per enclosure, since males fight and harass females. Females can share a large enclosure with multiple hides, basking spots, and feeding stations, but separate any tortoise that is bullied, hides constantly, or stops eating.
A baby tortoise can start in a smaller table, but build or plan for the adult size from the start: a baby Hermann's will need 6.67 ft by 3.33 ft as an adult. Even a baby enclosure needs a warm end, a cool end, a hide, and a water dish.
An adult sulcata at 30 inches needs at least 25 ft by 12.5 ft outdoors by the length rule, 312.5 sq ft, with a large heated shelter, but serious keepers recommend 600 sq ft or more outdoors for an adult sulcata. Sulcatas dig powerfully and bulldoze weak fencing, so outdoor walls must be sunk, strong, and tall.
Yes, at least one hide at each end of the enclosure. Hides let tortoises rest, escape heat, and feel safe, and a group needs one hide per tortoise plus one spare so no animal is forced to sleep in the open.