How Big Do Box Turtles Get?

Your baby box turtle is really small and piddly.

But, will he always be so tiny? How big do box turtles get?

In this article, we’ll let you in on everything you need to know about the size of a box turtle.

Key Takeaway:

The average common box turtle measures 5 to 7 inches (13 to 18 cm).

Box turtles grow to slightly different sizes depending on their species and whether they are male or female.

Are you ready to find out exactly how big your box turtle will get?

Then make sure you check out this next section.

How Big Do Box Turtles Get?

The average adult box turtle measures 5 to 7 inches (13 to 18 cm).

That’s right! They don’t get very big at all.

But, the best things come in small packages, and this is definitely the case with box turtles.

Some box turtles are slightly bigger and slightly smaller than average. The size of your box turtles will vary depending on the following factors.

  • Their gender
  • How old they are
  • Their species
  • What your box turtles eat
  • How well you look after them
  • The condition of their enclosure
  • How much exposure do they get to UVB light

More about good husbandry in just a mo. But before that, let’s take a look at some of these natural factors and how they affect the size of a box turtle.

Male and Female Box Turtles

There are a few obvious signs that help us tell a male box turtle from a female. For example, they have thicker tails and a concave dip within their plastron.

So what size are the males?

The adult male box turtle measures between 5 and 6 inches (13 and 15 cm).

Female box turtles have thinner tails than males and have flat plastrons. They are usually bigger than the males.

The female box turtle measures between 6 and 7 inches (15 and 18 cm). That’s right, the girls are bigger than the boys!

Depending on the species of the turtle, there may be some other factors that will help you tell a male from a female. The Ornate male box turtle has an inner claw on its back feet that is big and arched.

It is often possible to tell the difference between a male and a female turtle by looking at their markings.

For example, the Ornate male box turtle has red or orange eyes. The color of the male’s eyes often repeats on his head, legs, and neck.

In fact, it is not uncommon for the male box turtle to have red eyes while the female has brown eyes.

Growth Rate

Box turtles hit different size milestones throughout the course of their lives.

So how big are the eggs, babies, and teenagers?

Let’s find out more about their growth rate at different stages of their lives.

  • The average box turtle eggs are 1 to 2 inches long or (2.5 to 4 cm)
  • Baby box turtles measure 3 to 5 inches (8 to 13 cm). They are babies until they are about 5 years old.
  • Young box turtles measure 5 to 7 inches (13 to 18 cm) when they reach sexual maturity. This occurs from 5 years of age. They do not grow much after this.
  • Adult box turtles measure 5 to 7 inches (13 to 18 cm)

Most young turtles will grow at the rate of one inch per year (2.5 cm). As they get older, their growth will slow down to half an inch (1 cm) per year.

Gulf Coast Box Turtle

golf coast box turtle

Do you have a gulf coast box turtle at home?

Then you’ll be keen to know how big this fella will get so you can take good care of him. The average golf coast box turtle measures between 5 and 7 inches (13 and 18 cm).

These pet turtles are the largest type of American box turtle. They can grow up to 8 inches long.

Fancy getting to know these box turtles a little better?

Then here are some quick-fire facts you’ll love:

  • These box turtles are native to the areas around the gulf of Mexico
  • They love to be around water which is why you’ll find them in swamps and in marshes
  • In captivity, they live for around 40 years. Wild box turtles live for a lot longer, on average 100 years but some have lived for 138 years!

Eastern Box Turtle

What do we know about the size of the Eastern box turtle?

Eastern box turtles measure 5 to 6 inches (13 to 15 cm). They are some of the bigger turtles among their subspecies.

Here are some of our favorite facts about Eastern box turtles:

  • The eastern box turtle has slightly webbed feet at the base. Its hind feet have 4 toes and its front feet have 5.
  • It has a hooked upper jaw
  • This species does not breed until it is 10 years old
  • Eastern box turtles live between 50 and over 100 years
  • Female Eastern box turtles like other species of box turtles store sperm and may lay fertile eggs for up to four years after successful mating
  • Wild box turtles are native to the Eastern United States but they are popular in the pet trade which is why you will also see them in northern regions and other states

Ornate Box Turtles

Ornate box turtles are slightly different from other box turtle species. This is because the males are usually larger than the females.

The average adult size of an Ornate box turtle is between 2 and 6 inches (4 to 15 cm). These box turtles lay 3 to 8 eggs at various times throughout the year.

Here are some interesting facts about this box turtle:

  • The turtle’s body is protected by a dark brown shell with bright yellow markings
  • The males have bright red or orange eyes. The color of their eyes is usually repeated on the turtle’s head, legs, and neck. Yeah, the males are pretty snazzy dressers.
  • Their carapace has annual growth rings that make it easier for turtle owners to tell how old their pets are
  • They have a lifespan of 30 to 40 years

Three-Toed Box Turtle

box turtle on rocks

Are you a three-toed box turtle owner?

Then you’ll know that these turtles are super special as they have just 3 toes on their hind feet.

They measure 6 inches (15 cm). Three-toed baby box turtles measure 1.5 inches in length (4 cm) when they hatch.

We’ve already spoken about this box turtle’s unique toes, but here are some other facts that make it extra special.

  • These box turtles weigh 1 to 2 pounds
  • Wild box turtles live in marshes, grasslands, and wetlands in the US
  • Their lifespan is between 50 and 80 years but they can live for over 100 years

Your Box Turtle’s Growth Rate

We all want our turtles to be happy and healthy in their home. Both captive and wild turtles need to grow in the right environment in order to prevent illness and diseases such as metabolic bone disease.

How well you look after your pet box turtles will have a direct reflection on their growth rate. Here’s a list of some of the things your Common box turtle (terrapene Carolina) will need to grow properly.

Dietary Factors

Captive box turtles need access to the same balanced diet they would have in the wild. A proper diet for a healthy turtle will include the following:

  • Fruits like raspberries, apples, grapes, and papaya
  • Vegetables like leafy greens, butternut squash, and green beans
  • Insects like crickets, mealworms, earthworms, and grasshoppers
  • To enrich your box turtle’s diet, he will need to consume vitamin and mineral supplements
  • Fresh, clean water in a shallow water dish

Natural Sunlight

Your Common box turtle needs as much exposure to sunlight as he would have in his natural environment. This is about 12 hours of UVB sunlight per day.

His enclosure temperature should be between 70 and 90 degrees Fahrenheit or 21 to 32 degrees Celsius. This warmth will help him maintain his body temperature at 81 to 88 degrees Fahrenheit (27 to 31°C).

Yup, your turtle sure likes to feel toasty!

One end of his enclosure should be hotter than the other so he can have some time basking and sometimes cooling off. Let him out in natural sunlight whenever possible.

The Right Enclosure

Captive box turtles need to live in an enclosure that mimics their natural habitats. Your pet turtle will need a living space that is a minimum of 36 inches long and 12 inches wide (91 cm x 30 cm).

Your box turtle’s enclosure must have a basking area and a cooler area.

Clean your box turtle’s tank once every few months depending on how messy he is. Keeping the cage clean will prevent shell rot and help keep your turtle healthy.

Remember, most turtles carry salmonella bacteria, so always be careful when cleaning their enclosure and handling them. They are not suitable for children, the elderly, or people with a weakened immune system.

Wash your hands thoroughly and use bleach to disinfect your tub after washing out an enclosure to prevent getting a salmonella infection. Never wash your turtle’s enclosure in your kitchen sink.

box turtle cage

How Long Will a Box Turtle Live?

Box turtles are pets for life. If you’re thinking about adopting one, it is good to know how long the little guy will live to help you give him the proper care.

The average box turtle lives between 25 and 35 years. However, it is not unusual for a box turtle to live for a lot longer than that.

Many box turtles live for 50 years or longer and there is a number that lives for over 100 years. Eastern box turtles, for example, usually live for 50 years or longer.

Most of them will reach almost 100 years old or even older. Some are known to have lived for 120 years.

How Fast Does a Box Turtle Grow?

Box turtles are rather small. They usually measure between 5 to 7 inches (13 and 18 cm).

Because the lifespan of a turtle is so long, they usually grow very slowly. Most babies will grow at a rate of one inch per year (2.5 cm).

Box turtles are babies until they are about 5 years old. As they get older, their growth will slow down to half an inch (1 cm) per year.

When they become adults they tend to stop growing. Most are adults by 5 years of age but some species like the Eastern box turtle do not become adults until they are 10 years old.

Box Turtles and a Good Growth Rate

Box turtles grow properly when you feed them a good diet, give them enough sunlight, and keep them in the right enclosure.

So, if your turtle care ticks all the right boxes, how big can you expect your turtle to be?

This article has helped us to see that most box turtles measure 5 to 7 inches (13 to 18 cm). Slightly smaller species such as the Ornate box turtle grow to a maximum of 6 inches (15 cm) but some may stay as small as 2 inches (4 cm).

Did you find the information in this article interesting?

At Oddly Cute Pets, we are always striving to provide you with awesome guides about box turtles and other reptiles. For more tips about the best turtle and reptile care, check out our website.

Thanks for reading!

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