A19 VS A21: Light Bulb Offer a Popular Alternative

bulb reviews

A19 VS A21.The A19 and A21 are pear-shaped LED bulbs providing a common alternative to incandescent bulbs. The A21 looks a lot like the A19, and both can be connected to several of the same fixtures. These A-shape bulbs have a regular medium base that can be screwed into ordinary residential light sockets and table lamps.

Usually, these fixtures connect 40 to 60 Watt incandescent bulbs. If you need brighter light, you can need to use 100-watt incandescent bulbs. Incandescent bulbs do produce brighter light, but they are neither environmentally friendly nor pocket-friendly. The A-shape LED bulbs will reduce this issue and produce brighter light at lower power consumption.

You will get the ‘A’ bulbs in 60 Watt, 75 Watt, 100 Watt, 125 Watt, 150 Watt, and other similar power ratings. These bulbs are of the same pear shape, but of different sizes. While equivalent watt bulbs of both A19 and A21 can produce equivalent light, A21 is the most commonly available bulb in higher watts. High-watt A19 bulbs are more complex.

Although the size of A21 does not make much of a difference, it does not fit into certain fixtures. It is also a good idea to make sure that the fixture in your house will handle the A21 bulbs. But first of all, you have to determine whether you need an A19 or an A21. Here’s a comparison of the two that will help you make the right purchase.

A19 VS A21 Light Bulb

When comparing the two types of bulbs, we need to take into account features such as dimension, base size, degree of light distribution, etc. In addition, the contrast of the purchaser’s experience often adds teeth to the analysis. So, let’s get down to a detailed comparison between A19 and A21.

Dimensions: A19 VS A21

The letter A in these bulbs denotes the form, while the numbers that follow it denote the diameter at the widest point. The larger the distance, the larger the surface area. The higher the surface area, the greater the light distribution. Dimensions are also necessary to ensure that the bulb matches both the base and the head of the lamp. Bulbs with a higher dimension can also better contain the heat produced.


It is 2.4 inches in diameter and 3.9 to 4.3 inches in length.


It is 2.6 inches in diameter and 4.1 to 5.4 inches in length.

The Judgment – the right one is A21.

It has a larger dimension, which means that the heat produced can be well handled and the light can also be spread over a wider area.

Base: 19 VS A21

You ought to start measuring the base of the light bulb, as this will help you determine whether or not the current light fixture suits the light bulb. If the bulb is already in the fixture, you can take it along and fit it with the new bulb. Here is a comparison of the base sizes of A19 and A21.


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


This one, too, has an E26 light bulb foundation like the A19. This is the popular base size of light bulbs in the US.

The verdict:

Both light bulbs are of the same base size. So, you wouldn’t have a problem repairing any of them to your current home lighting fixtures if they were regular ones.

Light Distribution: A19 VS A21 Bulb

Light distribution is an essential indicator of the effectiveness of the light bulb because the LED bulbs are illuminated equally. To ensure that the lighting is sufficient, the size of the lamp should be commensurate with the size of the room.
Larger rooms require larger bulbs, smaller rooms require smaller bulbs. If the bulb is small relative to the size of the room, it will not produce enough light. If it was big compared to the room, it would seem too bright. So, the degree of light distribution tests the extent to which the light bulb can efficiently illuminate.


The A19 bulbs do not have reflectors. So the light produced by them moves in all directions , i.e. at an angle of 360 degrees. This can certainly light up a medium-sized room effectively.


Also, the A21 light bulbs do not come with reflectors. So, they too have a 360-degree light distribution. This, too, can effectively light up a medium-sized room. You can also have these bulbs at a higher wattage of 100, 125, or 150 watts. This makes the A21 ideal for illuminating larger spaces.

The verdict:

As far as light delivery is concerned, both A19 and A21 have the same efficacy. All you need to do is ensure the right wattage to light up a given place.

Since the A21 is available in higher wattages compared to the A19, better illumination with the A21 can be achieved if the area is wide. However, for each, the degree of distribution is the same.


There are many parallels between the A19 and A21 LED bulbs. They’ve got a regular base and light delivery. The only difference between them is the scale. The A21 is wider in length and diameter than the A19.

If there is no problem with the scale, you can consider all of them. However, in the event that you intend to fit the bulb into the holder of the light, the two can not be interchanged. A19 will fit into the holders of the A21 light, but not the other way around.

Experience of buyers: A21 VS A19

A21 A21

Longevity: There are not many longevity complaints.

Warm-up time: does not have the time to warm up. If you turn it off and then switch it on easily, it’s coming back with maximum brightness.

Enclosed fixture: Placing them inside the enclosed fixture makes them die easily. However, you can have those classified as safe to place inside the enclosed fixture.

Fitting: fits into a medium screw frame, which means almost all overhead lights in the building, but not table lamps.

Brightness: simulates daylight and creates a bright atmosphere within the room.


Longevity: It doesn’t last long. They’re beginning to go dead one after the next year or two. However, it also depends on how long you keep it turned on.

Warm-up time: does not have the time to warm up. If you turn it off and then switch it on easily, it’s coming back with maximum brightness.

Enclosed fixture: Placing them inside the enclosed fixture makes them die easily.

Fitting: fits into a medium screw frame, which means nearly all overhead lights in the house as well as table lamps.

Brightness: it depends on the one you want. There are lamps of Daylight and Soft White. Daylight variation is just too bright. Soft white might be the right one.

Frequently Asked Questions [FAQs]

Q1. Q1. Are all of these lights dimmable?

A2. Not all of the A19 and A21 are dimmable bulbs. If you’re looking for dimmable lights, you need to buy Dimmable lights.

Q2. That’s right. Are these bulbs emitting a buzzing sound?

A2. Buzzing sound is typically a problem with dimming LED lamps. So, if you’re not going to dim lights, there’s less risk of hearing any clicking sound.

Q3. Do these bulbs actually last a long time, like say 10 years?

A3. Most LEDs appear to have a lifetime of 10 years. However, it is based on the premise that you can only light it for 3 hours a day. So, if you leave it turned on for 6 hours or more, it won’t last for 10 years. In reality, it may be less than five years.

Q4. Will the A21 of 60 watts last longer than the A19 with the same wattage?

A4. There is a possibility that it may be because the amount of heat produced is the same in both, but in the A21 there is more room to distribute the heat. The internal electronics of A21 must therefore function under less heat than that of A19.


If you’re looking to replace the CFL or the Incandescent bulbs in your home, you can go either for an A19 or an A21. The only thing you need to see is that there is a better choice for A19 table lamps. You can go to any of the two for any other need.

However, if you need a high power bulb, it’s a safe idea to go for an A21. High-watt A19 is also more complex and might not last long due to intense heat generation.

So, this was a thorough contrast, from our side, of the A19 VS A21. So, which one have you selected for yourself? Let us know your experiences in the comments section below.

Mark Funk
Mark Funk is an experienced information security specialist who works with enterprises to mature and improve their enterprise security programs. Previously, he worked as a security news reporter.