What Size UV Bulb is Right For Your Bearded Dragon’s Tank?

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UV bulb size title card

If you’ve researched for more than 30 seconds on owning a bearded dragon, you know they need a UV bulb. Literally, every site and forum will tell you at least this much.

But they rarely tell you what type or size light you should use. We addressed the type of bulb and ballast you should use here. 

In this article, we’ll look at the appropriate size fixture and bulb for your scaly little friend’s home.

What Size UV Fixture Should You Use For A Bearded Dragon?

The correct size of UV light for a bearded dragon is determined by the width of its enclosure. There should be equal coverage across the entire tank. For a 36″ wide tank, use a 39w ballast, which measures approx. 35″ long. For a 48″ wide tank, use a 54w ballast, which measures approx. 47″ long.

You can see the 39w ballast and bulb we recommend here on Amazon.

You can see the 54w ballast and bulb we use here on Amazon.

While the wattage can vary by brand, it’s really the fixture length you want to pay attention to. The bulb should cover the entire width of the enclosure.

UV bulb
Fluorescent Light Tube

This is why we recommend fluorescent light tubes as your UV light source (you can see all the reasons here). You don’t want any sections of your beardie’s home lacking UV coverage.

You also need to allow your bearded dragon to move closer to or further away from the UV light as their UV needs change. 

You’ll find that sometimes your beardie will get as close as they can to the UV light, while at other times, they may choose to hang out in a hide, away from everything, including light.

Can You Use Multiple UV Bulbs In One Bearded Dragon’s Tank?

Yes, you can, but you shouldn’t need to if you use the correct type of bulb in the first place.

Typically, this question is asked by folks who purchased bearded dragon “starter kits.” Because these kits are designed to hit a price point and not give you the best possible options, they often include UV bulbs and fixtures that are far too small.

CFL bulbs UV bulbs
These are too small.

Instead of trying to supplement a light that is too small with more lights that are also too small, we advise you to set up the proper type of light in the first place.

If you are set on using multiple UV lights, buying a UV meter like this one is essential to ensure even UV coverage in your beardie’s home. You can read more about UV meters in our article here.

Inadequate UV light in your bearded dragon’s enclosure can lead to metabolic bone disease, among other severe health conditions.

Can You Use a Household Fluorescent Ballast and Bulb For A Bearded Dragon?

Never use a household fluorescent ballast or bulb for your bearded dragon. Bearded dragons require a high output UV light with specific minimum levels of UVB. Because household bulbs are not made to emit UVB as their first priority, they often fall far short of a bearded dragon’s UV needs.

This is a point that we often get pushback on. There are a lot of forum posts out there that tell people to buy their lights at Home Depot instead of buying reptile-specific products.

That’s a terrible idea. 

Yes, it will save you money. It will also cause long-term health issues with your bearded dragon.

Both your basking setup as well as your UV setup should be purpose-built for reptiles.

Along with nutrition, your lighting setup is the single most important thing to get right for a healthy, long-lived bearded dragon.

Do not risk your bearded dragon’s health by trying to save a few dollars on the lighting setup. It’s a one-time investment for the fixtures and then replacement bulbs once every six months.

If that expense is out of your budget, you should look at the total cost of bearded dragon ownership and then decide if you can afford to properly keep a bearded dragon in the first place.

The Verdict

In short, buy the right size UV light setup for your beardie’s home. It’s simple to do and will benefit your bearded dragon across its entire lifespan.

Ensure that your UV ballast spans the width of your tank and that you use reptile-specific lighting. If you do those two things, your beardie’s UV needs are well-covered!

Further Reading and Sources

Bearded Dragon Husbandry

Vitamin D3 and UV Exposure

Vitamin D and Skeletal Development of Young Bearded Dragons with Different UV Exposure Levels.

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Tim Steward is a life long pet owner who is currently raising a beautiful little beardie named Bacardi along with two Australian cattle dogs named Anny & Beans. Bacardi is one in a long line of bearded dragons that Tim has rescued, rehabilitated, and rehomed. Through Beardie Bungalow, Tim has helped thousands of beardie parents give the best possible life to their pets.

4 thoughts on “What Size UV Bulb is Right For Your Bearded Dragon’s Tank?”

    • Yes, that’s fine! It’s rare that the ballast is exactly the right size. Just get the size that’s closest and you’ll be just fine!

  1. Can we use two smaller lights to cover the width of the enclosure? We already bought one that’s way too small, but hate to think we wasted our money and can’t use it.


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