Whenever you are looking for a new car, there are a few things you have to take into account. One of them is the kind of light bulbs that your car needs. You might be wondering what the difference is between 921 and 912 light bulbs.

The 912 and 921 bulbs can be used in lieu of one another as they have the same T-5 wedge base. The wattage for 921 is 16.8 and it draws 1.4 amps, whereas the 912 bulb is only 12 watts but still only draws 1 amp; meaning that the light emitted from a 921 should appear brighter than that of a standard 912 bulb.

Socket Compatibility

So, the 921 vs 912 comparisons would be that the 921 emits a brighter light, but the 912 is more energy efficient. If you are looking for a light that will give you the brightest light possible, go with the 921. However, if you want to save some money on your electricity bill, go with the 912.

The socket type for a 921 and 912 are the same. So, if you have a car that uses 921 light bulbs, you can replace them with 912 light bulbs without having to worry about compatibility issues. At the same time, if you have a car that uses 912 light bulbs, you can replace them with 921 light bulbs without having to worry about compatibility issues.

What Is 921 Bulb?

This lamp is a BA9S base miniature wedge retrofit lamp that has a T-5 tubular glass envelope. It uses bi-pin technology and has a single contact on the side of the base. The light that is emitted from this bulb is very bright and it is often used as a backup light, tail light, or brake light in cars.

The 921 bulbs are significantly more powerful at 17 watts. With this nominal power, you will get more light output from your car. The 921 also has a higher CRI which means that the colors will appear more vibrant and natural.

Usually, drivers use these lamps as a backup reverse light or as a cargo area light. You can use them in your car’s side marker or even as a license plate light. These bulbs are also used in RVs, boats, and trailers.

The advantages of these bulbs are:

  • The light is very bright
  • The colors appear more vibrant and natural
  • These bulbs are very energy efficient
  • They have a long lifespan

The disadvantages include:

  • They are more expensive than other types of light bulbs
  • They can be difficult to find in stores

What Is 912 Bulb?

The 912 is a T5 Wedge Base Miniature Bulb that has been designed for easy replacement of existing wedge base lamps. This lamp uses bi-pin technology which means that it has two pins on the side of the base that are used to make electrical contact. The light that is emitted from this bulb is very bright and it is often used as a backup light, tail light, or brake light in cars.

912 bulbs provide a solid 1300 lumens of brightness. However, when we're talking about these types of lights, we need to choose the ones that are the most powerful. Usually, these lamps are also the ones that consume the most electricity.

The 912 is a great choice if you are looking for a powerful light bulb. However, you should keep in mind that it will consume more electricity than other types of light bulbs.

The benefits of 912 lamp include:

  • The color temperature is perfect for creating a natural light
  • The shape is perfect for use in cars
  • These bulbs are very energy efficient

The drawbacks are:

  • The light output is not as bright as other types of light bulbs
  • These bulbs are more expensive than other types of light bulbs

Specs Comparison

Nominal power

We'll start with the most significant difference in wattage between these two types of bulbs. 912 bulbs run at approximately 12 watts, while 921 bulbs use around 17 watts. That means you'll get improved visibility and lighting that's more powerful and easier for other drivers to spot when you're on the road.


The most distinguishing factor between 921 and 912 bulbs is their luminosity. The former emits 1600 lumens while the latter is 1300, due to its higher power rating. Although both options provide decent brightness, we recommend going with the more powerful lamps.

In case you need as bright bulb as possible, look for LED options.


When comparing the 921 bulbs to the 912s in terms of longevity, the 921s win. Our testing showed that, while the 912s have a long lifespan, they cannot match the duration of light for 921 bulbs. So, if you want a bulb with a longer lifespan, go with a 921. Even though it didn't do as well its counterpart in our tests, the912 held up extremely well under our strenuous tests.


912 bulbs are not only more affordable than 921, but they also provide a longer lifespan and dimmer light. Although the power rating, newer design, and brighter light output of 921 bulbs might be appealing to some people, the cheaper price tag and other benefits of 912 make them the better choice for many consumers.


How bright is a 921 bulb?

The 921 LED disc has 12 LEDs (5050 SMD) that offer an output of up to 190 lumens. The 3000K or 6000K temperature options provide direct 120° illumination.

How many amps does a 921 bulb draw?

We don't have the particular amperage rating for each lightbulb, but a general 921 incandescent light bulb uses up about 1.4 amps of power whereas a typical 921 LED only uses.

How do you remove a Type 921 bulb?

To remove the LEDs, simply grip them near the base of the bulb and pull them straight out. You may need a pair of gloves to avoid getting fingerprints on the bulbs. If they are stuck in the fixture, you may need to pull pretty hard.

Reviewed by Brent Ordway

Brent Ordway is an ASE-certified car technician. He has been working on cars since he was a teenager and loved helping people keep their vehicles running smoothly. Brent's skills as a mechanic are unrivaled. In 2022, he earned his place on the list of winners for the ASE Master Automobile Technician of the Year award.

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