Do T8 Bulbs Fit In T12 Fixtures?

Do T8 Bulbs Fit In T12 Fixtures

As light bulbs go, tube light fixtures are one of the long-lasting and reusable on the market. Although we all once used fluorescent T12 bulbs, they can be now upgraded to LED. 

But most LED tube lights nowadays come in T8 models. This might make you wonder if your T12 fixture is obsolete. 

As light fixtures are expensive and require hard labor to put up, you might be wondering do T8 bulbs fit in T12 fixtures? 

We are here to talk about that today. 

Tube Light Compatibility: Do T8 Bulbs Fit In T12 Fixtures

First things first, T8 bulbs fit in T12 fixtures. If the length of the bulbs matches, you can easily put a T8 bulb in a T12 fixture. 

But there are two other things you have to keep in mind. One is the ballast, and Two, are the connectors. This is where the problem kicks in. 

Where the Problem Will Occur

T8 bulbs, although lookalike, need no ballasts in general. They have built-in receptors that do the work for them. But a T12 fixture will have ballasts that are needed for a T12 bulb. 

It will turn a T8 bulb on, but in the long run, it will damage the bulb and cut down on the life span. 

The connectors are another issue too. Although both use the same G13 connectors, T12 fixtures have ballasts located on the connectors. So if you think removing the magnetic ballast will be a safe thing to do, it won’t. 

It won’t let the fixture work at all. Because the ballast works as the connector. 

The Best Way to Fit a T8 Bulb in a T12 Fixture

The best thing to do is to get a T8 bulb connector set. This will replace the T12 connectors without any hassle. 

Just a few unscrewing and placing the connectors is all you need to do because you don’t want your T8 bulb’s lifespan of 36,000 hours cut down to 2,000.

Can You Put T12 Bulbs in a T8 Fixture

Yes, you can. But the same problem will occur with the ballast. If your T12 bulb is the right size for your T8 fixture, you can fit it in the fixture. Remember to remove the ballast and connector of the T8 and replace it with a T12 set. 

Otherwise, it will also burn out and the lifespan of the bulb will decrease from 20,000 hours to 18,00 hours. 

Frequently Asked Questions 

Why are T12 lamps being discontinued?

T12 lamps and bulbs are generally fluorescent bulbs. Which uses up a lot of energy. With the development and efficiency of LED bulbs, congress voted out T12 bulbs to be discontinued due to being less energy efficient. 

Which is brighter T8 or T12?

The T8 bulbs produce 2,800 lumens which are higher than a T12 with only 2,300 lumens. That too in design lumens. Which makes the T8 brighter and more vibrant for color display than a T12. 

How do I know if my ballast is t8 or t12?

You can know your ballast information from its level. Look onto its level and you will find if it is a T8 or a T12. 

Are t8 bulbs being phased out?

Up until now, T8 bulbs can be found in the market. By 2023, the European market wants to take out the, T5 and T8 fluorescent models. But the LED ones will be available. 


T8 bulbs are the successor of the T12. They are slimmer, and sturdy and come in LED variants. And the T5 is the upgraded version of the T8. The best option is to get an LED variant of any of these bulbs as it cuts down on the electricity bill. And always make sure to convert the ballast too. 

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