How Big Do Iguanas Get? [Growth Rate & Growth Chart Per Age]

If you are considering an exotic pet like an Iguana, then naturally you are going to have some questions. Some of which will be about their size. How big does an Iguana get, what is their growth rate like and what are some considerations that you need to take into account? Here is all you are going to want to know

So, how big do Iguana get? The average iguana will range between 5 inches to 7 feet in length when fully grown. This wide variance depends on the species, with each ranging in color, shape, and size. Iguanas will typically reach their full adult size at three years old.

Iguana Size

There are currently 35 existing species with many available to keep as pets, so it is important to be aware of the species you have or plan to adopt.

If you’re looking at iguanas, first and foremost you need to consider the amount of space that you have available, and what you will provide for them.

Many owners like to keep their iguana in a 55 to 70-gallon tank for the first couple of years. They then go on to build a custom cage as their lizard increases in size.

If you have space in your home, you can prepare a room, where they are able to freely roam.

Of course, you will need to ensure that this is a safe environment, with no potential risks and opportunities for escape.

Let us now explore the topic further so that you can get a better understanding of iguanas, their growth, and their potential size.

Iguana Growth Rate

Iguanas grow at an incredibly fast rate; where much of their growth happens in the early years of their lives.

They are sexually dimorphic – which means that male iguanas are considerably larger than their female counterparts by the time they reach adulthood.

When speaking about the size of these creatures, we must be aware of the following terms:

  • SVL – snout to vent length
  • STL – snout to tail length (this includes the vent).

These are the two standard measurements used when understanding and interpreting the size of any reptile; including iguanas.

The green iguana is perhaps one of the most common to adopt as a pet. Let us now examine their growth rate to give you an idea of what to expect from this species of reptile.

You will notice how quickly they grow from the time they hatch to just a couple of years old. Green iguanas can grow up to 2 meters in total and are considered one of the largest species of iguanas.

The following table you help you to understand the type and size of enclosure that will accommodate your growing iguana throughout the various stages of their lives:

Iguana Growth Chart

Age SVL Body Length (Inches)  STL Body Length (Inches) Weight (Pounds)
When Hatching 2.5-3.5″ 6-9″0.2 lbs
Year 18-9″20-27″1-1.5 lbs
Year 2 11-12″28-36″2-4 lbs
Year 3 12-14″30-42″4-6 lbs
Year 4 24-16″35-48″5-8 lbs
Year 5 18-20″45-60″10-15 lbs
Year 6 20-22″50-66″14-18 lbs
Year 7+ 20-24″50-72″15-20 lbs

How Big Is A Full Grown Iguana?/ How Big Should My Iguana Be?

Generally speaking, Iguanas are large-sized pets; they have a sturdy build and resemble dragons.

The average large adult iguana (over the age of five) will reach a length of 5-7 feet and weigh about 6-8 kg.

Many people prefer their reptiles to be larger, as this indicates that they are healthy and will be able to handle more petting than a smaller-sized lizard.

Iguanas have muscular bodies, incredible-looking spiking beautiful long tails, and jowls.

Green iguanas are very interesting and can morph into a variety of colors, including red, blue, albino, and blizzard.

Smaller iguana species can also make ideal pets and are far easier to keep in captivity, let’s look at a selection of them:

  • The spiny-tailed iguana – this species comes from Mexico or Central America, it ranges in length from 4.9 to 40 inches.
  • The desert iguana – this species comes from arid regions of America. It can grow to 16 inches in length, but the tail accounts for most of its length.
  • The Fiji crested iguana – sadly, this species is endangered, its numbers are rapidly reducing. They come from dry forested areas in northwestern Fiji. It grows to 30 inches in length and weighs around 300 grams.

How Old Do Iguanas Get?

The average lifespan of an iguana varies between the different species. Each one takes different amounts of time to reach maturity. Some species only last a few years, while others can live up to sixty years.

Iguana Growth Rate

Again, a domesticated iguana will have a different lifespan to those that live in the wild. For better or for worse.

If you get a baby iguana, you will need to spend and invest a lot of time to being with them. Given the longevity of some species, it’s not a good idea to buy an iguana on a whim; you’ll need to consider that you will be looking after them for a long period of time.

The green iguana or common iguana species is the most popular reptile household pet in the United States.

The average lifespan of this reptile is 20 years in the wild; however, they don’t tend to do quite as well in captivity. Many die within the first year or two. One of the main reasons why many don’t survive long in captivity is that they are not easy to keep.

These pets have specialized heating and humidity needs. You must simulate their natural habitat as closely as possible.

This means ensuring that they have high humidity in their enclosure (minimum 70%) and you can increase the humidity of your iguana’s habitat by adding a pool of water to the enclosure.

They also require misting at least twice a day and bathing. Basking temperatures must be around 96-100 degrees Fahrenheit. Consistency is critical in maintaining these temperatures.

Aside from providing heat and humidity, you must provide sufficient lighting in the form of UVB lamps, and these need replacing every six months.

There are other much-needed accessories to buy for your iguanas, such as heat lamps and thermometers.

You must locate a reputable vet that is knowledgeable on reptiles. Your vet will be required to perform scans, blood, and fecal tests if your pet gets sick.

Getting the right vet is crucial in providing optimum care and ensuring they are healthy throughout the various stages of their lives.

Iguana Diet

Providing enough wholesome, healthy, and nutritious food is paramount to ensure that your iguana grows to its healthy weight and potential.

Fresh food is essential to ensure that you raise a healthy iguana.

It’s important to consider the diet of wild iguanas; who are exclusively herbivores. They do not eat any animal products, not even insects.

In fact, iguanas that have a high-protein diet are susceptible to a range of health issues and complications; like kidney failure.

When feeding your iguana, you need to seek out a high-quality and premium pellet.

This will form the majority of their diet. You’ll also want to provide dark leafy green vegetables (like spinach), a moderate amount of fruit, and also a calcium supplement (like this from Amazon).

Be sure to get into contact with your vet to ascertain the quantity that you should be feeding and supplementing to ensure your iguana grows at the correct rate and maintains a healthy weight.

It’s important to note that iguanas do not chew their food and in fact swallow it whole. So all food provided must be chopped or shredded into small pieces.

Be sure to provide plenty of fresh clean water, and change it frequently.

Selecting Your Iguana

Iguanas are commonly available from most pet stores, specialized reptile breeders, and some rescue centers.

More iguanas are ending up in rescue centers as owners fail to understand or prepare to meet the needs of their new pets.

You can expect an iguana to typically cost anywhere from $25-75. This is of course just for the iguana itself.

Regarding the size, be careful when you are selecting your iguana.

Do not be tricked into purchasing a small iguana, thinking or being told that it will stay to be that size into its adult years.

Iguanas grow very quickly, so they will soon be much bigger than the size you adopted them at.

Always look for the most active iguana. Check their eyes, make sure they are clear. Take note of their skin, making sure it is hydrated and elastic.

Red flags and iguanas to avoid adopting are those with low body weight, blood or mucus around the facial areas (mouth, nose, etc) any sores on their skin, and general apathy and lethargy.

Lastly, be sure to check in advance if you have any local veterinarians in the area with the reptile, or more specifically, iguana knowledge and experience.


As you can see, Iguanas are not the easiest pet to care for. They have numerous heating, humidity, misting, and lighting requirements, and they grow quickly in size making it difficult to accommodate them at short notice.

You need to plan and prepare in advance.

The green iguana is an example of a species that lives very well in the wild, but, doesn’t generally do as well in captivity.

It isn’t easy trying to replicate their natural environment. But that does not mean it cannot, nor should not be done.

These should not be reasons to prevent you from getting an iguana but be considered to ensure you know what you are letting yourself in for and know how to take care of them.

You must know what you are doing concerning their care and be willing to invest in their habitat.

These reptiles are amazing to look at, and many people want to be seen with one, but you don’t want to hinder this incredible reptile in any way.

As you can see, iguanas are considered to be large reptiles and can even grow as long as 7 feet in some cases!

But this is not always the case; it depends on the species.

There are smaller-sized iguanas available too, and they are just as beautiful as their bigger counterparts.

So ahead of any adoption, be sure to identify and research the species ahead of time.

Ultimately, iguanas have many excellent traits.

They are very intelligent and take to potty training very quickly. Unlike many reptiles, iguanas recognize their owners which can help you form a bond with them.

If you want a pet that isn’t too clingy and demanding, then an iguana is the pet for you.