Box Turtle Full Size: How Big Can They Get?

box turtle full size

The information is current and up-to-date in accordance with the latest veterinarian research.

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A box turtle’s size is indeed an important information that each turtle owner should know. I have researched a lot to get accurate information on box turtle size.

An adult box turtle can be 4 to 7 inches big on average. The growth rate and size are different for each subspecies.

In this article, I will discuss the size, growth rate of a box turtle, and how it is affected. If you are a new owner, or thinking about adopting a box turtle, this article might help you a lot.

Let’s jump to the main discussion.

Size Of Different Subspecies Of A Box Turtle

Box Turtle Subspecies Average body size Additional Information
Eastern Box Turtle 4.5 – 6 inches Eastern box turtles over 7 inches can be found.
Florida Box Turtle 4 – 6 inches
Gulf Coast Box Turtle 5 – 7 inches The largest gulf coast box turtle was 8.5 inches large.
Mexican Box Turtle 4 – 6 inches
Terrapene Carolina Putnami 4 – 6 inches
Three Toed Box Turtle 4 – 6.5 inches Adult male three toed box turtles are slightly smaller than the female ones.
Yucatan Box Turtle 6 inches
Aquatic Box Turtle Almost 6 inches
Desert Box Turtle 4 – 6 inches
Ornate Box Turtle 5 – 7 inches Female ornate box turtles are larger than male ornate box turtle
Spotted Box Turtle 4 – 6 inches Most of the spotted box turtle grow 4.5 inches long
Asian Box Turtle (Smaller) 5 – 7 inches
Asian Box Turtle ( Bigger) 9 – 12 inches

Pet Turtle Lifespan & Size Chart

pet turtle lifespan and size

If you want to get a printable version of this amazing chart, click here!

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Can You Determine The Sex Of A Box Turtle By Its Size?

It is not easy to determine a box turtle’s sex only by observing its body size. In most cases, female box turtles are longer than the male ones. It is not apparent for all the subspecies.

If you want to determine the sex of the box turtle, you may have to observe some other factors. For example,

  • Color of heads and legs
  • Color of neck
  • Color of its eyes
  • Difference in the plastron
  • Shape and size of its claws
  • Difference in the tail

By knowing these factors elaborately, and comparing the size of the box turtle, you can effortlessly determine the box turtle’s gender.

Does A Box Turtle Grow Throughout Its Life?

We all know that like all turtles, a box turtle has quite a long life. Maybe it’s not long like most others, but they have an average 50 years lifespan. Though it can vary with the difference of its subspecies, you can learn more from here.

You can observe a fast growth rate in the first five years. It may grow almost 4-5 inches during these five years. It will get matured, and will be able to reproduce.

If you think that’s it, then you are wrong. A box turtle can grow up to twenty years. That means you can measure its final size when it turns twenty.

Is Your Box Turtle Growing?

As I always say, being a pet owner endows you with more responsibilities. You have to observe your pet as your child. So you have to take extra care of your pet box turtle when it is growing up. But how do you know it is growing?

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There are two clear signs a box turtle shows when it grows up.

  • Shedding
  • Bigger Shell


A turtle’s shell consists of small scutes. When a box turtle starts growing up, the scutes starts getting more extensive. There is a thin covering over the scutes. In the process of growing up, the old surfaces shed, and new ones grow.

If you notice this kind of change, it means your box turtle is growing. Shedding is a natural process. Sometimes abnormal shedding can be observed among box turtles. In that case, you must consult a vet as soon as possible.

Bigger Shell

Turtles have a faster growth rate, and the changes can be observed without making any effort. When a box turtle starts getting bigger, its shell gets greater too. By measuring its shell size regularly, you will know it is growing.

Shell also indicates a box turtle’s health. A healthy shell means that the box turtle is fit and having a natural growth.

Growth Related Problems

A box turtle grows at a faster rate at an earlier age. But if you observe an abnormal growth, is it okay? Let me clear you the whole thing.

In some cases, a box turtle grows faster than it should be, and in many cases, it does not grow at all or grows slowly. If your turtle is growing fast, it is not a problem at all. To clear your doubts, you can consult a vet.

If your turtle is not growing or growing slowing, it is okay as long as the box turtle is healthy. Sometimes, like humans, some box turtles do not get the growth of others. But if the box turtle is unhealthy and is not growing, then it might be a problem.

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The main reasons behind this issue are diet and environment. Over diet and inadequate diet, both are harmful to health, and can stop your box turtle’s expected growth. Again, a smaller tank, dirty water, and insufficient light can limit the growth of your turtle. You should consult a vet as soon as you observe this kind of issue.

What Hampers A Box Turtle’s Natural Growth?

A box turtle grows comfortably with great care. Some factors can limit its expected growth or growth rate.

  • Food
  • Environment
  • Disease

These three factors can affect a box turtle’s health and growth. Harmful food and conditions are a curse to a box turtle. Again, your box turtle may not reach its full size due to some medical conditions.

To ensure a natural growth to your box turtle, you can follow the tips.

  1. Give sufficient food and minerals to your box turtle.
  2. Keep the tank’s water clean.
  3. Make sure it is getting enough sunlight.
  4. Do regular check-ups.
  5. In case of any health issues, consult the vet first.

As a box turtle owner, I always try to provide the best care to my pet. I tried to explain most of the facts related to the box turtle’s body size. I hope you find it helpful.

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About Author

Muntaseer Rahman started keeping pet turtles back in 2013. He also owns the largest Turtle & Tortoise Facebook community in Bangladesh. These days he is mostly active on Facebook.


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