How Long Does It Take for a Baby Turtle to Grow? (Full Guide)

Perhaps you just got a new turtle and are wondering how long it takes for them to achieve maturity. Besides, you want to tell if your turtle is growing and how big various turtle species can get. Knowing how fast a turtle grows will allow you to plan in terms of tank size and diet. 

A lot goes into determining the rate of growth in turtles apart from genetics. Turtles aren’t known for speed in movement. When it comes to growth, however, the more you feed the turtle, the faster its growth rate and vice versa.

This guide will delve into how long a turtle can grow from baby turtles to adults and how various factors determine growth.

How Long Does It Take for a Turtle to Grow?

While it will depend on the species, turtles reach their full size between 5 and 8 years. Turtles’ growth is not linear, meaning that more growth will occur at a certain age than another. For a majority of turtles, most of the growth occurs in the first four years. After that, it continues for more years but at a relatively slower rate. Almost every turtle will achieve their full size by the time they reach ten years old.

As a result, it’s essential to have a big enough turtle tank for your turtle. As is typical, the size of the turtle should determine the tank size. A general rule of thumb is to have 10 gallons for each inch of the turtle shell. Most turtle owners get the tank when the turtle is still tiny, not considering the turtle will outgrow the tank. Since the turtle might take up to 8 years to achieve its full size, it’s crucial to plan the tank size accordingly.

While this can costly, you should upgrade the tank when the turtle starts to grow out of the current one, or you should know the expected full size of your turtle species and purchase a bigger tank in advance.

How Fast Do Baby Turtles Grow?

Different turtles grow at different speeds, thus smaller species can take longer to grow than large species. However, turtle hatchlings are generally the same size, but they differ in that some grow only a few ounces while others reach hundreds of pounds. For example, the gigantic hawksbill sea turtle grows at an average rate of four inches a year. Red-eared sliders grow at an average rate of half an inch per year.

How Does a Turtle Grow and Develop?

Young turtles grow rapidly up until their sexual maturity age, after which their growth drastically slows down. With each passing year, their shells add a ring as the old epidermis layer gets replaced.  This layer allows deformations in case the shell experiences blunt shock, and it can regrow to provide more support. 

The Growth Cycle of a Turtle

Turtles are versatile creatures with the ability to live in both water and land. Whether they live in the sea, the desert, cold climate, or elsewhere, their life cycle is the same. Turtles go through 3 stages, including egg stage, hatching, and adult. Other organs don’t experience much growth over the years due to low metabolism rates allowing turtles to live for much longer even after they’ve long achieved their maturity. 

Here are the three life stages in detail.

Egg Stage

Turtles lay eggs either in water or digging holes in sand or mud. They then deposit the eggs in clutches and leave them to hatch. Some females can lay them, carry them for a year or more before laying them. Surprisingly, they bury them and leave without even protecting the eggs. A turtle’s egg has a leathery eggshell, which is tough. As a result, the baby needs to develop a tooth to break free of the eggshell. The tooth is a profusion on the nose that disappears shortly after birth.

Egg-Hatching Stage

After the egg is laid, the next stage is the egg-hatching stage, which takes about three months. For most turtle species, the hatchlings rear themselves – neither parent is involved. The temperature of the surroundings determines the sex of the hatchlings. When hatching occurs when the climate is hot, the hatchlings are certainly female. Typically, when the temperatures are low, the hatchlings are male.

New hatchlings scramble to safety once they are hatched. The major threat for them is hovering birds that are ready to sweep the newly hatched turtles before they reach the sea. This is why very few turtles reach maturity even though up to 80 eggs hatch at a time.

Adult Turtle

When the turtle hits its first birthday, it’s likely to have a complete shell. The shell starts to harden and to offer more protection. Aquatic turtles and land-based turtles may withdraw into the shells when they feel threatened or attacked. The turtles grow faster when young, but the growth slows down upon reaching sexual maturity. Once fully grown, turtles have fewer predators and can live for many years. Adult turtles are usually 5 inches long, e.g., the bog turtles to over 6 feet long like the leatherback sea turtle. 

Factors That Affect a Turtle Growth Rate

Healthy Diet

You can never overlook the influence of a healthy diet on a turtle’s growth. If you want the turtle to grow at the right pace, a balanced diet is vital. Remember that different turtle species feed different diets, so you should be aware of your species dietary needs. Turtles are either herbivorous, carnivorous, or omnivorous.

You need to do more research. Let’s take a red-eared slider, for instance. These are omnivores, so they need a balance between proteins, veggies, and fruits. Their diet should have meat, fish, insects, worms, pellets, aquatic plants, vegetables and fruits.

Painted turtles are also omnivores and will require about a 40% protein ratio in their diet. Box turtles, on the other hand, will need to have about 60% protein in their diet. Additionally, juveniles require more protein because their growth rate is higher than adults. Box turtle hatchlings, for instance, should primarily feed on protein (about 75%). Don’t forget to throw in some veggies and fruits occasionally.

Be careful not to feed your turtle too much protein, and this can cause problems. Too much protein in a turtle diet is likely to cause pyramiding, a condition that can cause deformations on its shell. A strict feeding schedule is also vital and should be maintained. Adults will feed about twice a week, while juveniles will feed every day.

Genetics (species)

Not all species and subspecies grow at the same rates. Still, turtles of the same species and sex that feed on the same diet and are brought up in the same environment can grow at different rates. So, if one turtle looks a bit smaller to you, it’s probably in their genetic composition, and there’s nothing you can possibly do. For instance, snapping turtles grow quite faster at the beginning and could achieve 12cm shell size at age 2. This is too high considering a species like a red-eared slider that will achieve the same size at age 12. Just ensure the diet is right, provide enough sunlight and check for defects to ensure the turtle grows to its maximum. 

Environmental Conditions

Maintaining conditions such as water quality, UV exposure, enclosure space, basking spots, temperature, and hiding spots are all essential factors for growth. Having the right amount of UV exposure ensures that a turtle grows to its maximum. UVB light plays a central role in the production of Vitamin D3, which is needed to convert calcium in the body. When raised without adequate UVB rays, the turtle may suffer improper bone growth, softshell, metabolic bone disease, shell rot, and other defects. Enclosure space is also important as the turtle needs more space to thrive. 

Turtles living in small spaces may not achieve their maximum growth. The tank should be four times wider and two times deeper than the turtle’s width and length, respectively. If the tank holds more than one turtle, ensure to increase the dimensions by at least 25% for each turtle. The water needs to be clean for swimming and drinking. Ensure to check the chemistry to reduce toxicity caused by ammonia and other impurities.

Sex and Age

The sex of a turtle determines how fast they grow. Usually, female turtles grow larger than male turtles. Age is also an important factor. As said earlier, turtles grow much faster in their first few years and slow down as they grow.

How to Measure a Turtle

When we measure how much the turtle has grown, we measure the size of its plastron. Noting the size of your turtle is helpful to ensure your turtle is getting enough nutrition. Here are the exact steps on how to measure a turtle.

  1. Flip the turtle to access the plastron. Remember, turtles dislike being in the upside position, so you should be fast. In nature, an upside-down turtle is almost a dead turtle. So, you need not stress the turtle by keeping it for too long. If the turtle feels too stressed out, it may hiss or bite.
  2. Grab a measuring tape and measure from the tip of the plastron to the end of the plastron
  3. If you want to measure the growth of the carapace, you just do the same, but this time, you start from the carapace tip, all the way up the curve to the carapace.

Congratulations! You just measured your turtle successfully.

How to Determine the Age of a Turtle

When you measure a turtle, the goal is to help you know whether the growth curve is normal. With the data, you can know what to add or remove from its diet plan. Check out these tips on how you can determine the turtle’s age.

  1. Flip the turtle upside down. Be quick, so the turtle doesn’t get stressed.
  2. On the plastron, observe the abdominal area located around the middle at the lower half. Confirm the 8 sections of the plastron and count the third section. It has two halves.
  3. Work with one of the halves.
  4. Check the rings on that half and count them.
  5. Remove one from the rings you’ve just counted, and that’s likely to be the age of your turtle. For instance, if you count seven rings, then your turtle is six years old.

Keep in mind that this method is more accurate for turtles in captivity than wild ones. Still, the method may mislead for homegrown turtles if they have a growth spurt. Although this method may give a better idea about a turtle’s age, it may not always be correct. You can also use scratches and marks to estimate the age of older turtles.

Growth Rate of Popular Pet Turtle Species

How Fast Do Red-Eared Sliders Grow?

You probably got your first red-eared slider and wondering how fast they grow. Red-eared sliders grow at a rate of 3 to 4 centimeters during their first few years. Upon reaching adulthood, they only grow at 1 inch per year until they reach the full size.

By age 2, they can be as long as 2.3 inches or 6 cm. By age 3, red-eared sliders could reach up to 4 inches (10 cm). At 4 years, the red-eared slider should reach about 4.5 inches (11.5 cm). Females grow up to 12 inches while males will not exceed 10 inches.

Red-eared sliders females achieve sexual maturity at 6 inches while males mature at 4 inches. Both typically achieve the length within 6 years. It could go for up to 8 years for this species to reach its maturity length. Generally, the growth rate varies from one individual to another, but the variation is usually by an inch or two.

Age (in years)Average shell length (in cm)

How Fast Do Painted Turtles Grow?

Painted turtles see the fastest growth as hatchlings. Juveniles painted turtles grow at an average rate of about 1.2 inches per year, which is incredibly fast. Upon hatching, the turtle will start growing really fast, and by age 1, they have grown to around 5 cm. by age two, they should read about 7 cm. A 4-year-old painted turtle should reach about 8 cm and 9cm by age 5.

This species reaches sexual maturity at around age 10 when they reach 12 cm in length. After reaching sexual maturity, the growth rate drops to about 0.1 cm per year. Over the next ten years, the turtle can grow an additional 3 cm with the right growth factors. The full size of an average painted turtle is about 15 cm, but some may grow as longer as 25 cm (10 inches).

Age (in years)Average shell length (in cm)

How fast do snapping turtles grow?

Snapping turtles are a popular pet know for growing very quickly. In captivity, they have a reputation for overeating, perhaps the reason they grow up so quickly. As with most turtles, they grow the fastest during their first years in life. Of course, individual growth for each snapping turtle will largely depend on how much you feed them.

These voracious eaters will grow to 12 – 15 cm (5 – 6 inches) in the first two years. Over the next 15 years, the shell length could reach up to 35 cm (14 inches). Adult snapping turtles can grow up to 19 inches and weigh up to 40 kgs.

Snapping turtle growth chart

Age (in years)Average shell length (in cm)

How Fast Do Map Turtles Grow

Common map turtles are generally small, with adult males measuring about 4 inches. Female map turtles, on the other hand, are slightly bigger, with the adults obtaining lengths of 7 inches. Upon hatching, the male’s plastron measures 3cm while the females’ plastron measures 2 cm on average.

When they reach age 1, the male’s plastron reaches about 4.2 cm while the female’s measures 4.4 cm. by age to the age of two, both the male and female measure an average length of 6 cm. at age 4, the male plastron should reach about 7.5 cm in length while the female’s plastron averages 9.7 cm. in other words, it’s at age 4 that you should notice a difference in length between a male and female common map turtle. 

When they reach age 5, the male should have grown slightly to about 8 cm while the female maintains the faster growth to about 11 cm. Females reach sexual maturity at age ten at an average length of about 20 cm. Males reach maturity at 5 to 6. 

Map Turtle Growth Chart

Age (in years)Average shell length in males (in cm)Average shell length in females (in cm)

How Fast Do Box Turtles Grow

As with most turtles, common box turtles, scientifically referred to as Terrapene Carolina, grow the fastest as juveniles. When they reach a certain age, they see a slower growth rate. During the early stages, particularly 0 to 5 years, common box turtles grow at a steady rate of 1 cm (10 mm) per year.

From age 5 to 10, the turtle will grow at a slower but steady rate of 0.8 cm (8 mm). from age 10 to 15, expect the turtle of this species to grow at a rate of about 0.2 cm per year.

The carapace grows at a steady rate in the first five years. By age 5, the turtle should have a carapace length of about 7.5 cm. By age 10, the standard box turtle should attain a carapace length of about 12.3 cm.

When they reach age 10, the growth rate of carapace slows down significantly as the turtle grows a few additional centimeters over the course of its life. Box turtles achieve maturity by around age 7, but some could take up to age 10. At maturity, expect the carapace length to reach about 12.7 cm to 15 cm. check out the box turtle growth chart below.

Box turtle growth chart

Age (in years)Average shell length (in cm)

Why Do Wild Turtles Grow Slower Than Pet Turtles?

According to observations and studies, almost all pet turtle grows faster than turtles in the wild. This is mainly due to two main reasons – the proper diet and regulated temperature.

In their natural environment, hibernation puts a break to their growth. Being ectothermic creatures means they can’t produce their own heat – they depend on the heat in their environment. Turtles hibernate in winter, during which their metabolic rate slows down and growth stops.

Pet turtles, on the other hand, don’t need to be at the mercy of nature. Owners provide them with artificial UVB light, a water heater and a balanced diet. When winter comes, their water temperature is regulated, and UVB bulbs provide them with heat. So, they don’t need to hibernate. Precisely, wild turtles get less than nine months to grow, while pet turtles need 12 months. Besides, turtles in the wild need to search for a variety of food for a balanced diet, and they must scavenge for them.

So, ample food, balanced diet, heat, UVB bulbs and constant care are the main reasons why pet turtles grow much faster compared to their wild counterparts.

How to Boost a Turtle Growth

Turtles lack the speed of movement as well as the speed of growth. However, they are resilient creatures that grow steadily. Most owners hardly notice when the pet attains maturity. Are you wondering how you can intensify the turtle growth rate?

Check out these tips.

Keeping the Record

As mentioned in this guide, measuring your turtle size from time to time can help you plan accordingly. Over time, you can compare the data with previous data to know whether the turtle is following a regular growth pattern. If something is amiss, you know whether you need to add or remove something. When the conditions are working, you know you are doing it right.

Measure the Tank Size

When you have the shell size, you can easily plan for the tank size. As a rule of thumb, you need 10 gallons of water. For each inch of their size, ideally, a 20-gallon water tank will suffice for juveniles. However, they might grow faster in the first few years, so they might need to be ready for upgrades. Measuring the tank vs the shell size helps you know if the water is enough or not.

Maintain Water Parameters

Turtle growth will largely depend on the optimal water quality and temperature. For example, you need to keep the water temperature between 750F to 850F for turtles to thrive. Besides, you need to have a water testing strip to measure the chemistry in the water and condition it to suit the turtle requirements. Ideally, the water needs to be free of ammonia and chlorine. Ensure there’s effective filtration in the tank to remove waste in the tank. One of the best practices for a clean turtle tank is regular cleaning, if possible twice a week.

Feeding and Basking

Turtles will also grow fast when provided with a balanced diet with a balance of proteins and vegetation. Some species will thrive on a carnivore diet. Others prefer a mix of plants and proteins, and the rest are vegetarians. For most species, however, the young turtles feed on more proteins while adults eat more veggies. A supplement is necessary to boost their growth, including providing occasional live prey. Also, ensure the turtle has a basking area to ensure adequate UVB. A lack of this will lead to Vitamin D3 deficiency and weakening of bone and shell.

Maintain Optimal Temperature Conditions

your turtle will grow faster if you can provide the right temperature for the tank at around 75 degrees Fahrenheit and up to 85 degrees Fahrenheit for the basking area. These temperatures are optimal for their metabolic processes, and their absence can stunt the reptile’s growth or become ill. 

Monitor the Turtle’s Health

Illness not only delays the growth process but can also lead to loss of body weight especially if the turtle is unable to eat. Be on the lookout for any signs of illness such as open-mouth breathing, cloudy or closed eyes, mucus around their mouth or nose and listlessness. If your turtle is exhibiting any of these symptoms, you should immediately get in touch with a reptile vet. 

Wrap up

Health and diet play a key role in determining a turtle’s growth rate. These factors are under your control. If you can feed your turtle a healthy diet and be on the lookout for any symptoms of illness, you are well on your way to supporting your turtle’s growth. Other factors such as genes and sex play an important factor in determining how big your turtle will eventually be. by trying to mimic the environmental conditions in a turtle’s native habitat, you will be providing adequate conditions for optimal growth. 

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