The BEST LIGHT BULB: A19 vs A21

Light Bulbs are the only source of light for us during night time which is powered using electricity or you may have small portable electric lamps powered by cr2032 battery. In this article, we are going to help you find out which are the best of these two. The Two Bulbs That we are going to help you review are A19 vs A21 light bulb.

While both of these light bulbs are available as LED type, you may also buy them as regular types. People usually find it difficult to choose between A19 and A21, because they are confused with the differences. So we are going to help you decide which is the best light bulb – A19 vs A21?

Dimensions of A19 vs A21 Light Bulb

Let me tell you an amazing fact. Do you know that the name of the bulb is determined by its design? The letter A represents the shape of the bulb, whereas the next 2 digits followed to show the diameter of the bulb at its widest point. The width of the Light Bulb is the most important part. Because the width of the bulb determines the amount of light that is to be delivered throughout the room.

And whenever you are looking for a bulb for your table lamp, you need to know the exact dimension to make sure that the bulb fits within the lamp head. The size of the bulb is to be determined carefully to contain the heat that is generated by the bulb.

A19 light bulb philips

A19 Bulb Dimensions

So now as you how the name of a light bulb is decided, let us discover more. The A19 light bulb has a radius of 1.2 inches or a diameter of 2.4 inches. Similarly, the length of the light bulb is 3.9-4.3 inches. The dimensions in millimeters are 112.7mm in length and 69.5mm in diameter.

A21 Bulb Dimensions

The A21 light bulb has a radius of 1.3 inches and a diameter of 2.6 inches and its length if about 4.2 to 5.5 inches. The dimensions in millimeters are 78.5mm in diameter and 139.7mm in length. So it shows that it is a bit longer than the A19 Bulb.

So from the comparison of the above two it is clear that A21 is the winner because of its larger size. You might be wondering how can that be an advantage right? Well, as we said the larger the size, the more heat it can manage. So A21 bulb can manage the heat produced better than the A19. But still, many users prefer A19 bulb and they say it is more comfortable.

A19 vs A21-BASE comparision

Well, you need to decide the base of the light bulb carefully because that is what determines the light fixtures it can be fitted to. If you do not have a bulb in your light fixture, then you must be sure about the size of its base. Both the A19 and A21 are ordinary light bulbs, so it might be a little confusing to you while deciding the best one out. So we are here to help you decide if both light bulbs have the same size or not.

A21 light bulb

A19 bulb

The A19 comes with an E26 light base. Well, talking about the size structure, it is a normal size when compared to the standard base sizes available in the US.

A21 bulb

The interesting part is that A21 also comes with an E26 base. so it is the same as the A19. The main reason why E26 base size bulbs are so popular is that it is the standard base size for almost every socket in houses.

Distribution Degree: A19 vs. A21

Now, this is the most important point of comparison because this is what decides the amount of light needed for a room which makes the room shine perfectly.  Just imagine your hall which is too large and requires a bulb that spreads light to each and every corner of the hall, so a small bulb won’t deliver such light. Or imagine a small room where it would be way too bright. The regards degree of distribution will also help you decide your final choice when you need to know how far the light needs to reach. Always make sure that the light needs to be just right, not too much and not too less.

Philips light bulb

A19 bulb

Well, the A19 bulbs do not have a built-in light reflector which means that they can not emit light in a complete 360-degree angle. So this tells us that this light is only suitable for medium-sized rooms and is not enough for large rooms.

A21 bulb

The A21 bulb comes with a built-in light reflector that helps even distribution of light throughout the room. So by placing the A21  into your lamp holder, you can decide the correct angle at which sufficient light will be delivered to the whole room without leaving out any corner.

Any of these bulbs are enough and provide a satisfactory amount of light to the entire room. So whenever deciding the bulb make sure to check on the degree of distribution to ensure that the light delivery performance is amazing.

A19 vs A21 Pros and Cons

Both of the light bulbs are commercially used by people. The main reason people prefer both of them is because they meet the standard bulb base and also have the same light distribution. So the only difference between both of these light bulbs is that the A21 is larger in diameter when compared to A19, which means that A21 can give you better light in larger rooms when compared to the A19 bulb.

But there is one thing that people need to keep in mind before buying any one of these. If you are planning to use them into a lamp or lamp holder keep in mind that you have to choose only one of them. This is because Some lamp holders support A19 bulbs whereas some lamp holders prefer A21 bulbs. If you interchange them there might be a problem and it won’t be good. Because A21 is a bit big for an A19 lamp holder and A19 bulb is a bit small for an A21 lamp holder. So just check them before buying them.

Which is The Best Bulb ? A19 vs A21

We have helped you clear all the confusion between both of them. Now we think that you have a clear idea about which bulb you should be buying. Our opinion on this is the A21. It is a bit larger than the A19 bulb which will help you provide light at each and every corner of your large rooms. I hope we gave you a clear idea about the one you should be buying.

Recommended Light Bulbs

We want to make the work easier for you, so here below are the best light bulbs that you can get right away from amazon to make your home shine brighter.


If you want to know more about bulbs, by more we mean history and blah blah. Go check the complete guide by Wikipedia on Incandescent light bulb.

Leave a Comment

Your email address will not be published. Required fields are marked *