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A19 VS A21: Which Light Bulb is Better for You? [All Points Covered]

A19 VS A21

The A19 and A21 are pear-shaped LED bulbs that offer a popular alternative to incandescent bulbs. The A21 looks much like the A19, and both can be attached to many of the same fixtures. These A-shape bulbs have a standard medium base that you can screw into ordinary residential light sockets and table lamps.

These fixtures usually attach 40 to 60 Watt incandescent bulbs. If you need brighter light, you may need to use 100 Watts incandescent bulbs. Incandescent bulbs do produce brighter light, but they are neither environmentally friendly nor pocket friendly. The A-shape LED bulbs can mitigate this problem and produce brighter light at lower power consumption. 

You can get the ‘A’ size bulbs in 60 Watt, 75 Watt, 100 Watt, 125 Watt, 150 Watt, and other equivalent power ratings. These bulbs have the same pear shape, but different sizes. Although equivalent wattage bulbs of both A19 and A21 can produce equivalent light, A21 is the most commonly available bulb in higher wattages. High wattage A19 bulbs are more complicated.

Although the size of A21 does not make much of a difference, it may not fit in some fixtures. Therefore, it is a good idea to make sure that the fixture in your house will be able to accommodate the A21 bulbs. But, first of all, you need to decide whether you need an A19 or an A21. Here is a comparison, A19 VS A21 that can help you decide the best buy.

Light Bulb A19 VS A21

While comparing the two types of bulbs we need to take into account features like dimension, base size, degree of distribution of light, etc. Moreover, comparing the buyers’ experience always adds teeth to the review. So, let’s get down to a comprehensive comparison of A19 and A21.

1. Dimension: A19 VS A21

The letter A in these bulbs denotes the shape, while the numbers following it denote the diameter at the widest point. The higher the width the larger is the surface area. The larger the surface area the greater is the spread of light. Dimensions are also important to make sure that the bulb fits the base and also the lamp head. Bulbs with a higher dimension can also better contain the heat generated.


It has a diameter of 2.4 inches and a length of 3.9 to 4.3 inches.


It has a diameter of 2.6 inches and a length of 4.1 to 5.4 inches.

The Verdict – A21 is the better one.

It has a larger dimension which means that it can manage the heat generated well and also distribute the light over a wider area. 

2. Base: A19 VS A21

You need to consider the measurement of the base of the light bulb as this will help you decide whether the existing lighting fixture will fit the bulb or not. If there is already a bulb in the fixture, you can take it along and match it with the new bulb. Here is a comparison of the base size of A19 and A21.


It has an E26 light bulb base, which is a medium, light bulb base size considered to be the standard base size in the US.


This too has an E26 light bulb base like the A19. This is the common base size for light bulbs in the US.

The Verdict: Tie

Both the light bulbs have the same base size. So, you would not have any problem in fixing either of them to your existing lighting fixtures at home, if they are standard ones. 

3. Distribution of Light: A19 VS A21 Bulb

Distribution of light is an important measurement of the efficacy of a light bulb since LED bulbs illuminate evenly. For illumination to be appropriate, the size of the bulb should be commensurate with the size of the room.

Larger rooms need larger bulbs and smaller rooms need smaller bulbs. If the bulb is small compared to the size of the room it will not produce enough lighting. If it is large compared to the room, it would appear too bright. So, the degree of distribution of light measures how far the light bulb can effectively illuminate. 


The A19 bulbs don’t have reflectors. So, the light emitted by them travels in all directions, i.e in a 360 degrees angle. This can definitely light up a medium-size room effectively.


The A21 light bulbs also don’t come with reflectors. So, they too have a 360 degrees distribution of light. This too can effectively light up a medium-size room. Nevertheless, you can get these bulbs in higher wattage of 100, 125, or 150 Watt. This makes the A21 suitable for lighting up bigger rooms. 

The Verdict: Tie

As far as the distribution of light is concerned, both A19 and A21 have the same efficacy. You just need to ensure the right wattage to light up a given area.

Since the A21 is available in higher wattage compared to A19, you can get better illumination with an A21 if the area is large. However, the degree of distribution is the same for both. 

A21 Bulb VS A19: Similarities

There are a lot of similarities between A19 and A21 LED bulbs. They have a standard base and light distribution. The only difference between them is in size. The A21 is larger in length and diameter compared to the A19.

If the size is not a problem, you can consider any of them. However, in case you are planning to fit the bulb into the lamp holder, you cannot interchange the two. A19 can fit into the A21 lamp holders, but not the other way around.

Buyers’ experience: A21 VS A19


  • Longevity: There are not many complaints regarding longevity.
  • Warm-up time: Does not have a warm-up time. If you turn it off and then switch on quickly, it just comes back with full brightness.
  • Enclosed fixture: Putting up inside an enclosed fixture makes them die fast. However, you can get those marked as safe for putting up inside an enclosed fixture.
  • Fitting: It fits into a medium screw base which means almost all overhead lights in the house, but not table lamps. 
  • Brightness: It simulates daylight and creates a bright environment inside the room.


  • Longevity: It does not last long. They start going dead one after one after a year or two. However, it also depends on how long you are keeping it switched on. 
  • Warm-up time: Does not have a warm-up time. If you turn it off and then switch on quickly, it just comes back with full brightness.
  • Enclosed fixture: Putting up inside an enclosed fixture makes them die fast. 
  • Fitting: It fits into a medium screw base which means almost all overhead lights in the house as well as table lamps. 
  • Brightness: It depends on which one you choose. There are Daylight and Soft White bulbs. Daylight variety is too bright. Soft white may be the right one. 

Frequently Asked Question [FAQs]

Q1. Are all these lights Dimmable?

A2. Not all A19 and A21 are dimmable lights. If you are searching for dimmable lights you need to buy those which are marked as Dimmable.

Q2. Do these bulbs emit a buzzing sound?

A2. Buzzing sound is usually a problem with dimmable LED lights. So, if you are not going for dimmable lights, there is less chance of hearing any buzzing sound.

Q3. Do these bulbs really last long; like say 10 years?

A3. Most LEDs claim to have a lifespan of 10 years. However, it is based on an assumption that you would light it only for say 3 hours a day. So, if you are keeping it switched on for 6 hours or more, it is not going to last 10 years. In fact, it can be less than 5 years.

Q4. Would an A21 of 60 Watt equivalent last longer than an A19 of the same wattage?

A4. There is a chance that it would since the amount of heat generated is the same in both, but in the A21 it gets more space to disperse the heat. So the internal electronics of A21 have to work under less heat compared to that in A19.

Difference Between A19 and A21: Conclusion

If you are looking for replacing the CFL or Incandescent bulbs in your house, you can well go for either an A19 or an A21. The only thing you need to see is that for table lamps A19 is a better option. For all other usage you can go for any of the two.

Nevertheless, if you need a high power bulb it is a good idea to go with an A21. An A19 of high wattage is often more complicated and may not last long due to extreme heat generation.

So, this was a detailed comparison of A19 VS A21 from our side. So, which one did you choose for yourself? Let us know your experiences in our comments section below.