How Big do Red-Eared Slider Turtles Get? (With Pictures)

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How Big Do Red-Eared Slider Turtles Get

These turtles are popular as pets due to their hardy nature and wide range of colors and patterns.

The red-eared slider is a type of turtle found in the United States and Canada.

They can grow anywhere from 2 to 12 inches long, with females usually being larger than males.

There are many factors that impact the size of these aquatic turtles, including genetics, diet, availability of food sources such as insects or worms, water temperature (too hot or too cold), and climate conditions such as seasons for those living in temperate locations.

the difference in sizes from baby, juvenile to the adult stage

How Big Do Red Eared Sliders Get in the Wild?

In the wild, red-eared slider turtles have a wide range of habitats and they usually are smaller than what we find in captivity.

Their natural environment is ponds with slow-moving waters with soft bottoms and vegetation.

These conditions do not allow the red-eared slider turtle to grow as fast or larger than they are able to in captivity.

How Big Do Red Eared Sliders Get in Captivity?

Red-Eared Sliders that live in captivity grow much larger than they do in the wild.

A red-eared slider turtle that is kept in a large enough tank or pond can grow to be 1 feet long, weighing between 4 to 6.5 pounds.

Red Eared Slider Growth Chart

Life stage of a Red-Eared SliderAgeSize In Diameter
Baby Turtles3 months1 inch
Juvenile Turtles1-4 years4.5-5 inches
Adult Turtles5 years+8-12 inches

Factors That Influence Red Eared Slider’s Growth

There are some factors that we need to consider when we are talking about a red-eared slider growth rate and these include:

1. Habitat Conditions

baby red-eared slider near a pond

Wild red-eared slider turtles thrive in aquatic environments that mimic their natural habitats.

The water should be clean and it should have a proper pH balance.

Water temperature must be between 70 to 85 degrees Fahrenheit, with water being often being warmer than the air and having a current.

For growing red ear slider turtles, using a turtle tank that is at least one-hundred gallons is the best option.

Also, if the tank is outdoors it must be protected against predators and direct sunlight so that the turtle does not get overheated or sunburned on its shell.

The turtle tanks should also be kept in an area that gets filtered UV light, where the water temperature is lower than that of outdoor water.

Hands down the best tank to use for red-eared sliders is a stock tank with an airstone, good filtration, and a heater.

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RELATED READ: The Best Tanks for Red-Eared Sliders

2. Turtle Diet

The size of the red-eared slider turtle depends on the types of food that they eat.

Diet is especially important in juveniles growing red-eared slider turtles.

When they are young, red-eared slider turtles should be fed only every other day and they should be offered a variety of food types including live or frozen bloodworms, live crickets or mealworms, and a commercial turtle diet formulated for growth.

Frozen turtle food is a good choice when they are young and leafy greens for when they are adults.

Examples of these foods include Repto-min, Hikari Turtle Sticks, and a variety of other turtle foods from the local pet turtles store.

Hatchling red-eared slider turtles have different diets than those that are juveniles or adults since they start out feeding on small insects in addition to algae.

Common foods for hatchling red-eared sliders are snails, tadpoles, worms, mosquito larvae, and other invertebrates.

Adult red-eared slider turtles should be fed every day except when they are shedding because this can contribute to their growth.

The best proper diet for adult red-eared sliders is live foods, commercial pellets, fish, shrimp, or krill.

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RELATED READ: The Best Food for Red Eared Slider

3. Age of the Red-Eared Slider

The younger the turtle is when it is kept in captivity, the larger it will grow once it matures.

A red-eared slider that is kept in captivity before it has reached one year of age will grow to its full potential.

One that is kept after it reaches its first birthday may never reach the same size as another red ear slider turtle.

How Can You Tell the Age of a Turtle?

juvenile turtle versus baby red-eared sliders

The age of a red-eared slider turtle can be determined by its size, shell shape and shell color.

The growth rings on the shell can indicate a turtle’s age.

The pattern of the growth rings will tell when the red-eared slider turtle has reached sexual maturity and how old it was when it laid its last clutch of eggs.

The average slider turtle will reach sexual maturity at around five to seven years old.

At this time, the turtle will be about three to six inches long.

The age of a red-eared slider turtle can also be estimated by measuring its carapace.

A red-eared slider turtle that is six inches long will be between five to seven years old.

One that is about five inches long will be between three to four years old, while one that is less than five inches will be around six months to one year old.

A turtle that is five inches long is considered an adult slider turtle although their shell growth will not be as long as it will be when they reach six inches.

The average red-eared turtle species can grow to about twelve to fifteen inches. A red-eared slider turtle that is less than six inches long will never become as big as an adult red-eared slider turtle even if it is well fed.

4. Gender of the Turtle Impacts Growth

full grown red-eared slider

The gender of a red-eared slider turtle can be distinguished by looking at its tail and the underside of its shell.

A female red-eared slider turtle can be identified by the lack of tail between her plastron and tail.

A male red-eared slider turtle has a longer tail and its tail can easily be seen between the turtle’s plastron.

The male red-eared slider turtle is also flat on the underside of its shell while a female red-eared slider turtle is more rounded.

RELATED READ: 10 Basic Tips For Caring For Baby Red Eared Sliders

Can Gender of a Turtle Affect Its Growth?

Male red-eared slider turtles tend to grow faster, while females tend to grow bigger.

This is because they need to be larger in order to mate.

A female red-eared slider turtle can lay eggs up to four clutches each year while a male red-eared slider turtle can mate up to 150 times a year.

The average red-eared slider will grow around two inches a year when it is younger and then barely grow at all once it reaches its full size.

The red-eared slider turtle will reach maximum sexual maturity at around five to seven years old while it can live up to 30 years.

The size of your red-eared slider turtle will determine how many red ear slider turtles you should have in one tank.

6. Lighting System in the Turtle Tank Can Impact Growth Rate

Red-eared slider turtles need a special lighting system in order to help them grow.

A full spectrum fluorescent UVB light that is around ten to twelve inches above the tank is recommended, usually done in a basking area.

This helps to mimic their natural proper habitat.

The lighting for your red ear slider turtle should be on about 12 hours a day to provide them with enough food and it will also help your turtle to grow faster.

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When Are Red-Eared Sliders Fully Grown?

A red-eared turtle will grow for the first few years of its life and then barely grow any larger afterward.

Red-eared sliders are fully grown when they are about twelve to fifteen inches long.

One that is six inches long will be between five to seven years old.

One that is about five inches long will be between three to four years old, while one that is less than five inches will be around six months to one year old.

The average red-eared slider turtle can grow to about twelve inches.

RELATED READ: How Long Can Red-Eared Sliders Go Without Water

How Big Are Baby Red-Eared Sliders?

A baby red-eared slider turtle can grow up to three inches in its first year.

How Big Are Juvenile Red-Eared Sliders?

A juvenile red-eared slider turtle can grow up to six inches in its second year.

How Big Are Adult Red-Eared Sliders? 

An adult red-eared slider turtle can grow up to twelve inches in its third year.

RELATED READ: How to Set Up a Turtle Tank

Red-Eared Slider Turtle Facts and Information

  1. Red-eared sliders can live as long as 30 years
  2. Females carry up to four clutches of eggs at a time and typically lay one egg every two days
  3. The aquatic turtles have flexible shells that allow them to squeeze through tight spaces between rocks or logs in streams or ponds
  4. Their skin is made up of a meshwork of small scales rather than large plates like other turtles
  5. Red-eared slider can be considered an invasive species
  6. Turtles are not the best pets for small children due to their fragile shells

Behavior and Temperament

Red-eared slider turtles are known for their tendency to be aggressive toward other turtles.

When a red-eared slider turtle is not getting enough red-eared slider turtle is an omnivore, which means it eats both plants and meat.

Snails are a common food for adult red red-eared slider turtles that can grow up to twelve inches in their third year.


appearance of a red eared slider

Red-eared sliders are unique among turtles because they have red or pink stripes on their ears.

They have a long tail that is usually darker than the rest, ranging in size from four to fifteen inches, red-eared sliders have a long neck and streamlined body.

In their natural habitat, wild turtles, roughly one-third of adults have a red line underneath their eyes.

Tail and shell colors also vary, according to age and location.

Red-eared sliders are the largest of all pond turtles.

RELATED READ: Do Red Eared Slider Turtles Hibernate?

Tips to Buying a Red-Eared Slider

Red-eared slider turtles are becoming a popular pet as they are easy to care for, inexpensive, and now available at most pet stores and venues.

You should only buy a red-eared slider turtle from a reputable breeder or seller, as they can carry salmonella.

Ensure that the turtle is healthy by checking that it has clean eyes, ears, and nose without any discharge.


Red-eared slider turtles grow at different rates and reach adulthood at different sizes.

The gender of the turtle also impacts its growth, with male turtles growing faster than female turtles while females grow larger.

Turtles need a special lighting system in order to help them grow and should have around 12 hours of light per day.

Red-eared slider turtles grow fastest when they are young, but will stop growing at around 12 inches.