How Big Does An Iguana Get? 6ft. Max

Unlike domestic pets, exotic pets have special needs. Therefore, it is critical to understand their basic requirements and prepare in advance before getting one. To know how big an enclosure you should get for your adult iguana, you must first know how big it can become as an adult. Hence the question “How Big Does An Iguana Get?” begs to be answered.

For instance, if you consider getting an iguana as your pet, it is paramount to know what they require to stay healthy and happy in captivity. Getting a cage for your iguana would be your number one priority.

And to get the right size, it is critical to know the size of the iguana. Many people wonder how big their iguana is expected to grow. 

As such, we came up with this article to help you understand the actual size of an iguana from birth to adulthood. Keep reading!

Cute Reptiles as Pets x
Cute Reptiles as Pets

How Big Can an Iguana Get?

There are two major species of iguanas, “The green iguana and the lesser Antillean species. The green iguana average size is 5-7 feet, while the average size of the lesser Antillean is 4-5 feet. Males tend to get bigger than female iguanas. While the male iguanas can grow for up to 7 feet, females only grow to 5 feet. In captivity, iguanas can extend for up to 6 feet.

Iguana Size by Age

It takes approximately four years for iguanas to reach their full size. However, some continue growing until they are 7-8 years. 

Iguana’s growth rate is different at every stage. For instance, iguanas tend to grow fast during the first 3-5 years. From there, their growth becomes almost stagnant for some time before they gradually grow again.

How Big Does An Iguana Get?
The green iguana average size is 5-7 feet, while the average size of the lesser Antillean is 4-5 feet.

Here is a table showing the average size and weight of a green iguana at every stage.

Age Weight (Pounds)Iguana  Length (Feet)
0-6 months≤1 to 1.5 0.5 – 2.5
1-2 years 4 – 62.5 – 3
2-3 years 6 – 83 – 3.5
3-5 years 8 – 183.5 – 5.5
5-7 years 18 – 205.5 – 6
Sizes of Iguanas by age

How Long Does It Take For An Iguana To Grow Adult Size?

The size of iguanas depends on their species. However, they all reach adult size at the age of 3-4 years. After four years, some species experience stagnant growth while others grow until seven years.

During the first three years, iguana’s growth rate is rapid. Some reach their full size of about 5 feet long and can weigh up to 18 pounds at this age. 

However, the iguana’s growth rate depends on several factors such as the environment, genetics, and diet. Therefore, the growth rate of one iguana will be different from another. 

When Does Iguana Stop Growing?

Iguanas are more likely to grow until they are eight years. However, at the age of four, they may stop growing for some time and then start growing again. Even if your iguana stops growing at the age of four, be prepared for it to start growing some more until they are eight.

Factors That Affect the Growth of Iguanas

Imagine babies born the same day and within the same hour. They may weigh the same at birth but different in a few days or months. Even for iguanas, the same situation occurs. Iguana’s growth rate can be affected by three significant factors: tank, UVB light, and diet.


Providing a stress-free environment for your iguana is essential to promote a healthy growth rate. Stressed iguanas tend to have a retarded growth.

As such, it is critical to provide your iguana with a large tank that they can comfortably move around.

A good thumb of rule is to provide a tank that 1.5Lx1.5Hx 1W larger than your iguana. Baby iguanas can be comfortable in a 20-gallon tank. However, adult iguanas require a tank that is 12 feet long and 8 feet high to keep them stress-free.

Also, iguanas are highly arboreal. Thus, their tank should be large enough to accommodate enough branches to climb. 

Related read: The cost of keeping an iguana

iguana bathing in a pool
The best way to house an adult iguana is to built it an open outdoor enclosure

UVB Light

UVB lighting is indispensable when keeping iguanas in captivity. Lack of adequate UVB can incredibly cause health issues to iguanas.

As such, it is imperative to provide your iguana with a 10-12 hours UVB light. Inadequate UVB highly contributes to metabolic disease in iguanas.

As a result, your iguana growth rate deteriorates and can even cause death. Therefore, if you plan to keep an iguana as a pet, consider investing in a good lighting product such as Zoo Med’s ReptiSun

Last update on 2021-11-22 / Affiliate links / Images from Amazon Product Advertising API

Related read: Types of iguanas for pet

Iguana Diet

A good diet is vital for a healthy iguana. Just like a bad diet can affect humans, it is with iguanas. 

How fast your iguana grows depends on how well you feed it. Lack of a good diet will cause health issues and stagnant growth. 

Iguanas are herbivorous. Thus, a good diet consists of plants, especially leaves, vines, and fruits. 

Iguanas mainly live on leaves, vines, little fruits, and flowers in the wild. In captivity, it is necessary to ensure that their diet consists of plenty of calcium and Vitamin D3.

Calcium and Vitamin D3 promote health, growth, and strong bones. A good diet for iguanas may include mustard greens, alfalfa hay, kale, parsley, turnip green, collard greens, escarole, dandelion, swiss chard, and any other plant rich in calcium.

Beware of vegetables such as lettuce, spinach, iceberg, and cabbage containing goitrogens. Goitrogen is a chemical substance that enlarges the thyroid gland, thus causing goiter or hypothyroidism.

An iguana eating vegetables
An iguana eating vegetables

Iguana’s healthy diet should contain 80-90% dark green leafy vegetables and 20% fruits and flowers. Some good fruits and flowers that you can offer your iguana are mangoes, melons, kiwi, banana, blueberries, strawberries, hibiscus, dandelion, geraniums, and others.

Fruits, flowers, and vegetables containing goitrogen should not be a regular diet. Instead, it would be best if you offered those occasionally as a treat.


How big is a full-grown iguana?

A full-grown iguana can measure approximately 5-7 feet in length and weigh up to 20 pounds. How big an iguana gets depends on species, sex, habitat, diet, and genetic. Iguanas are dimorphic. Thus, the male tends to get bigger than the female. 

How big does an iguana get in a year?

How big an iguana gets in a year depends on its age. During the first three years, the iguana growth rate is usually rapid.

However, the iguana stops growing or grows slowly from the fourth year. During the first 1st year, an iguana can grow from 6 inches to 28 inches, and only 50-60 in the 5th year.

How much does an iguana cost?

How much an iguana costs depends on the gender, breed, and species. Green iguanas are the most common pets and thus inexpensive. A green iguana can range between $10 – $99.  Other rare morphs such as translucent albino have been priced at $3000.

Final Sentences

Exotic pets such as iguanas come with great responsibilities. They have special needs that their owner must meet to thrive in captivity. 

Knowing how much your iguana could grow in the future is critical to understanding how much space they may need. 

It is, therefore, necessary for you to know how big your iguana is likely to grow for you to prepare enough space for them. 

We hope this article will help you understand if the iguana is the best pet for you.