How Big Do Red-Eared Slider Turtles Get: Size Cycle, Factors, and Growth Rate

Red-eared slider turtles can grow to be quite big- up to one foot long and can weigh up to 550 grams or more. Size is determined by several factors, including gender, age, environment, diet, and nutrition. Age and sex are the two most important contributors to size for red-eared slider turtles.

Factors Affecting How Big Red-Eared Slider Turtles Get


Feeding and water intake also have an impact on turtle size. Slider turtles are specialists when it comes to their diet. Apart from insects and other small animals, they also enjoy eating vegetables and fruit. As a result, you shouldn’t overfeed them as this can lead to obesity or health problems.  

In addition, water intake is essential for these turtles as they get their water from the soil. Ensure their enclosure has a good amount of wetland or damp areas so they can cover themselves with mud to keep cool in summer and warm in winter.


Vegetables are an essential part of a slider turtle’s diet. A good mix of different vegetables will help the turtle grow big and strong. Be patient – they will grow bigger over time! And try to feed them fresh produce instead of processed foods, as this can help keep their diets healthy and nutritious. Additionally, feed them high-quality turtle food to help promote growth and development.

Live Food

Red-eared slider turtles are more likely to eat insects and other live prey. The more giant the turtle, the more prey it will consume! This size-dependency is due to different hormones running in their systems which dictate how much calcium they need for growth. Plus, live prey means there’s more chance for them to learn about hunting, tracking, and survival.


As slider turtles get bigger, their diet and the size of their tank will change as well. Different environments will significantly affect turtle growth – forested areas tend to be smaller than coastal habitats, for example. Weather conditions can also play a role in turtle size; warm weather increases growth rates while cold weather decreases them. For example, those that eat live prey tend to be smaller than those that feed on frozen/frozen-thawed food. 

In addition, the temperature significantly impacts the growth of turtles – the colder it is outside, the smaller they will get due to their lower metabolic rate (meaning they use less energy). It’s also crucial for turtle owners to provide adequate lighting and space – a larger tank allows them to grow bigger.


Gender plays a vital role in the growth and development of turtles. Female slider turtles tend to be larger than males and grow faster than during the first year of their life. Males typically grow larger than females and reach their adult size at around two years old. Females can grow up to three times the size of males and live up to 25 years in captivity. 

Size of Red-Eared Slider Turtles at Different Life Stages

Size of Baby Red-Eared Sliders

Baby red-eared sliders are only less than an inch during their first months but can grow at 3 to 4 centimeters per year, so be sure to monitor them closely. You can keep track of your babies by removing their water bowl every night and checking their weight regularly. 

Size of Juvenile Red-Eared Sliders

Juveniles will grow about half the size of adults over their first year, so buy the right slider for your turtle tank or enclosure. Red-eared sliders are typically about 12 inches long and weigh just over one pound as juveniles. So, be prepared for your turtle to get quite big – it may not take long to reach that size! Remember that red-eared sliders grow quickly, so be prepared to monitor your turtle’s growth closely. 

Size of Adult Red-Eared Sliders

According to the IUCN, adult red-eared sliders can grow around a foot long. Make sure to keep an eye on their growth – as they get bigger, red-eared sliders can get quite destructive, so be prepared to put up with some messes! 

When Are Red-Eared Sliders Fully Grown?

On average, sliders reach their adult size in 8 years, but the size and color of the slider can vary greatly. Sometimes sliders reach their full size within their first year, while others may take up to two years. In addition, red-eared sliders can have wild and variant colors, so it is essential to monitor your turtle’s growth for any unexpected changes closely.

Growth Rate of Red-Eared Sliders

Red-eared sliders proliferate and can reach up to 1.6 inches in diameter within their first year! Keep your red-eared slider warm and dry, as they naturally prefer more relaxed environments. And if you forget to feed them, their natural diet consists of insects and worms. These factors are significant to the growth rate of your turtle pets. So while it’s essential to take your part, there’s no need to fret – these turtles will take care of the rest!

Red-Eared Sliders Compared to Other Turtles in Size

Regarding size, remember that not all turtles are created equal – red-eared sliders are typically smaller compared to other common American turtles like the snapping turtle and wood turtle. However, they can still grow quite extensively throughout their lifetime.