What is the Difference Between A15 and A19 Light Bulbs (Compared)

When you ask for a light bulb from the store, you might be posed with a lot of questions like the watts of the bulb, LED or CFL, type of base, and so much so on. Most of us can get really confused with these queries and we might only know one or two of these specifications.

The most used bulb spec is the wattage. It is easier to tell the wattage you require and get the product. But you might get the wrong type of base and the diameter of the bulb may not be suitable for your socket.

Popularly, A-type LED bulbs or Incandescent bulbs with diameters 15 and 19 are used. So, let us discuss the difference between A15 and A19 bulbs in this article.

What is the Difference Between A15 and A19 Light Bulbs

What is the Difference Between A15 and A19 Light Bulbs

The difference between A15 and A19 light bulbs is their diameter. The A15 bulb has a diameter of 15/8 inches and the A19 bulb has a diameter of 19/8 inches. You might still be wondering what the A is and which diameter of the bulb it refers to. Since light bulbs come in different shapes and sizes we shall now understand the specifications used to denote the bulbs.

Understanding the Light Bulb Shape Specification Codes

Every shape and size of the bulb is designed with a unique structure and according to it, the light bulb codes vary. The A-type bulb is referred to as an Arbitrary shape which is specified by the following characteristics:

  • It has a spherical end section connected to the neck by a radius
  • The end section radius is greater than the spherical section 
  • The center of the end section is outside the bulb
  • The spherical end section radius is tangent to the neck and the curve of the bulb sphere.

So, when the shape of the bulb is designed in the above-mentioned manner, it is defined as an A-type bulb. Now let us talk about the diameter specified in the bulb nomenclature.

The numbers specified near the alphabet A denote the maximum diameter at the widest point in the lamp. If you look at an A-series light bulb, you can find it bulged near the top. The part where it has bulged to the maximum is measured. 

The diameter is specified in two units. In the US, you can find the diameter in eighths of an inch (1/8th of an inch), and in the rest of the world, it is mentioned in mm. 

A15 Bulb Size

The size of the A15 bulb is 15/8 inches in diameter which can also be denoted as 1 7/8 inches. In other parts of the world, it is mentioned as 48mm. As for the length of the bulb, it is around 3.39 inches or 86mm tall. 

A19 Bulb Size

The size of the A19 bulb is 19/8 inches which can also be denoted as 2 3/8 inches. It is defined as 60mm in the rest of the world. As for the length of the bulb, it is around 4.33 inches or 110mm tall.

Wattage and Brightness in A15 and A19 bulbs

A15 bulbs are available from 5.5W to 7.5W and they can produce a brightness of 300 lumens to 810 lumens according to the wattage.

As for the A19 bulbs, you can get more than 9W, and the brightness can go up to 1600 lumens.

The brightness can also vary according to the light bulb type like LED light bulbs, compact fluorescent light bulbs, incandescent bulbs, etc. 

A15 Vs A19 Bulbs: Comparison

Difference Between A15 and A19 Light BulbsA15 Light BulbA19 Light Bulb
SpecificationA15 BulbA19 Bulb
Diameter15/8 Inches or 48mm19/8 Inches or 60mm
Length3.34 Inches or 86mm4.33 Inches or 110mm
Watts5.5W to 7.5W>9W
Brightness300 – 810 lumens1600 lumens
Color Temperature2700K to 5000K2700K to 5000K

What Type of Bulb Base can be used for A15 and A19 bulbs?

Although the diameter of the bulbs is different for both A15 and A19, they have the same base size. The base refers to how the bulb is connected to the socket.

Usually, A15 and A19 bulbs use the Standard-medium E26 base which refers to the Edison screw base. The number 26 refers to the width of the base which is 26mm.

You can also find the bulbs mentioning the bulbs are Medium Base which refers to the E26 type.

Both A15 and A19 bulbs are commonly used for general lighting purposes in homes, businesses, and outdoor spaces. The difference in diameter may affect the spread and intensity of the light, with A19 bulbs typically providing a wider and brighter light compared to A15 bulbs.

However, both types of bulbs are compatible with the same fixtures and sockets, making it easy to interchange them as needed. 

When purchasing A15 or A19 bulbs, it’s important to check the base size to ensure compatibility with your existing fixtures. As long as the base size is the same (E26 or medium base), you can choose between A15 and A19 bulbs based on your specific lighting needs and preferences. 

Where can you use A15 and A19 bulbs?

Both the A15 and A19 bulbs can be used in normal household lighting uses like lamps, ceiling fans, light fixtures, and lighting in the hall, bedroom, etc. According to the brightness requirements, you can choose A15 or A19.

If you are lighting up a large space like a hall or room, you might have to use an A19 bulb. If you want a dimmer light just at your bedside or for your lamp, then you can go for the A15 bulbs.

Additionally, the A19 bulbs are typically larger and more powerful, with a higher lumen output, making them suitable for larger areas that require brighter lighting. On the other hand, A15 bulbs are smaller and less powerful, making them perfect for more localized and dimmer lighting needs.

Both the A15 and A19 bulbs are available in different types, including LED, incandescent, and CFL, so you can choose the one that best meets your energy efficiency and longevity requirements.

Ultimately, the choice between A15 and A19 bulbs will depend on the specific lighting needs of the space in which they will be used.


These are the differences between A15 and A19 bulbs. Now you will be able to choose the right type of product to light up your house. Hope this guide has enlightened you about the popular bulb codes and specifications.

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