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This book is packed with easy-to-understand information on selecting and setting up a habitat, feeding, breeding, and all other aspects of proper leopard gecko care.

How Old Is Your Leopard Gecko (With Growth And Size Charts)

Did you get a new leopard gecko, but you’re unsure how old it is?

Are you looking for ways to tell the age of your gecko pet?

Leopard geckos are challenging to tell precisely their age without getting the birth date from the breeder.

Still, it’s not impossible if you know what to look for.

Fortunately, we built this article to answer the question: How old is my leopard gecko?

You can tell how old your leopard gecko is by measuring its length and weight. Although this isn’t foolproof, it will give you a good idea of your leopard geckos general age.

Look ahead for more details on this topic.

how old is my leopard gecko

2 Ways To Tell How Old A Leopard Gecko Is

There are two main ways to tell how old your leopard gecko is.

It depends on several factors, but using these two in conjunction will give you a good idea.

Measuring To Determine Age

Measuring your leopard gecko best way to tell age, but this doesn’t work well after 18 months.

At this point, they’re fully grown.

Sure, to some degree, they continue to grow after adulthood, but it’s minimal compared to the rest.

AgeLength for MalesLength for Females
Birth3″ inches3″ inches
1 month4″ inches4″ inches
3 months5″ inches5″ inches
6 months6″ inches5″ – 6″ inches
9 months7″ inches6″ inches
12 months8″ inches7″ inches
18 months10″ – 12″ inches8″ – 10″ inches

Note: This is only a generalization.

There’s always wiggle room depending on the situation and individual leopard gecko.

Measure your leopard gecko from the nose to the base of the tail to get a good measurement.

We don’t typically include the tail as leopard geckos drop their tails off when threatened.

They may not even have a tail the moment you measure them.

Don’t worry! They grow back (although they never fully match the patterns of the body).

Using Weight To Determine Age

As with length, guess a leopard gecko’s age by their weight.

This also only really works with younger leopard geckos.

However, the weight is affected by outside factors, so use this in conjunction with other methods.

Consult this chart.

AgeWeight for MalesWeight for Females
Birth2-5 grams2-5 grams
1 month10-20 grams10-20 grams
3 months20-30 grams20-30 grams
6 months30-40 grams30-40 grams
9 months40-50 grams35-45 grams
12 months55-65 grams40-50 grams
18 months60-80 grams50-70 grams

Careful with using weight for age at any point past adulthood.

There are so many factors at this point; it’s useless to use this factor.

Female leopard geckos will gain weight before getting pregnant.

After laying eggs, females are underweight.

Males and females both lose some weight around the shedding as they don’t eat at all.

Overfeeding will cause them to weigh more.

Stick with feeding your pet two insects for every inch they are long every other day.

Underfeeding (usually with too small of insects) keeps the underweight. It’s the same with illnesses.

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Colors And Patterns

Colors and patterns on the leopard gecko can give a hint as to their age as well.

First, look at the patterns on the geckos.

Most adult leopard geckos will have spotted bands rather than full bands around their body.

If you don’t see spots, the leopard gecko is under a year old.

The type of coloration also is affected by age.

From birth to adulthood, they move from a rich and bright form of their normal coloration to a more muted coloration.

After adulthood, this mellowing of colors continues throughout the rest of their life.

On standard leopard geckos, they add yellow to their color more and more as they age.

Note: This is only guaranteed with more typical leopard geckos and not all morphs.

And once you know the age of your pet, check out our post on the leopard geckos average lifespan.

How Long Does It Take For A Leopard Gecko To Reach Its Full Size?

The simple rule is 18 months.

They’ll grow somewhat throughout the rest of their lives, but this doesn’t always affect their size a lot.

Size is different from sexual maturity.

Males may reach this as young as ten months old. 

Females usually reach it after a year old.

It’s possible to encourage this growth with a consistently higher temperature of 90° degrees Fahrenheit (32° C).

Higher humidity helps too.

But this doesn’t mean they’re healthier.

The growth happens fast or slow as long as the habitat’s set up correctly.

Growth speed doesn’t matter. 

teen leopard gecko

How Do You Know If A Leopard Gecko Is A Boy Or Girl?

Since size and growth varies somewhat based on gender, you may want to know how to tell a leopard gecko’s gender.

The biggest and easiest test is to check for hemipenal bulges.

On the underside of their bodies, where the body meets the tail, males will have two lumps.

Gently lift their tails and look for the two lumps.

Alternatively, shine a light through the top of the tails at the spot and look from underneath.

The light shows you the shadows if there are two hemipenal bulges better than lifting the tail.

This light method is preferred for handling the tail.

Leopard geckos will drop their tails if they get too stressed, and such handling may do this.

And if you’ve never experienced a tail drop, we have a post on what to do when leopard geckos drop their tails made just for you.

Better to use the light and only do the check when they’re used to you.

There are more ways to check for leopard gecko sex.

We’ve written on how to sex a leopard gecko in-depth for anyone wanting to check out the full post on that topic.

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We hope you enjoyed learning about how to tell how old your leopard gecko is.

Looking at the charts above, you may be able to get a good idea of your pet’s age.

The best way is still to contact the breeder you bought it from.

Most breeders keep excellent records of all of their pets.

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