A21 vs a19 bulbs: A19 vs A21 Light Bulbs | Blog

A19 vs A21 Light Bulbs | Blog


Lighting Essentials

​​The A19 and A21 bulbs have the same shape, but the diameter of the first bulb is 2.375 inches. The larger model is 2.625 inches in diameter. You’ll also notice the base height difference in the A19​ vs A21 comparison. The A19 is 4.13 inches tall, while the A21 is closer to 5 inches. You’ll get a similar user experience when you buy any bulb with these names, including LED bulbs. For more details please read on.


The A Base Is One of the First Light Bulb Designs

Even though the A-style base was one of the first introduced with the invention of the light bulb, it continues to be one of the most popular designs. It uses a standard threaded style that works well for convenient connections to fixtures.

Consumers can quickly remove or install light bulbs with minimal risk of injury. Even if the base gets stuck in the fixture, it is reasonably easy to take out – even if the bulb breaks.

Except for the longer neck and larger bulb, the
A21 light bulbs look precisely like the A19 version. The size is identical enough that you can install them in the same fixtures or use them for similar lighting needs.

Most fixtures get paired with 40W or 60W bulbs that produce up to 800 lumens, but you can go with something brighter when needed because of this design element. The only trouble in the p​ast has been the heat generated by 100W incandescent bulbs. Ceiling fans, floor lamps, and even some sockets weren’t designed to withstand those temperatures.

LED manufacturers create an equivalent wattage experience, measured in lumens, that fits in fixtures while eliminating the heat-generation issue. Higher lumens still use the A21 shape, much like higher wattage designs do, to ensure the technology works as intended.

For most consumers, the size of the light bulb base isn’t the consequential part of the buying decision.  A19 and A21 bulbs work in virtually all standard fixtures.

What you’d want to review is if the fixture is compatible with the wattage equivalent you need for your home, business, or outdoor application.

What to Know About Wattage Equivalency

Wattage, or watts, is a measurement of electrical power. When you have one watt, you experience one joule transferred per second. If you’re looking at electrical applications and circuits, it’s equally easy to translate current to voltage.

If you have a traditional 40W incandescent bulb with an A19 base, it will convert 40 joules of energy into heat and light output each second.

The distinction between heat and light output when comparing incandescent and LED technologies is what generates the energy-saving difference.

If you have a 40W incandescent bulb and a 10W LED bulb that produce equal lumens, you’re saving 30 joules per second.

You could purchase a 40W LED bulb, but the power and brightness generated by that technology could light up an entire backyard. That’s why wattage is no longer considered an essential measurement of energy. You need to know the lumens rating for a direct product comparison.

With an incandescent bulb, some designs lose up to 90% of the joule expenditures as heat. That means you only get 10% of the energy converted to light with A19 or A21 designs.

LEDs generate the same light with much less wattage because the heat generation process doesn’t occur.

What Light Bulb Ty​pes Are Available in A19 and A21 Bulbs?


When you’re ready to upgrade to LED lighting, you’ll likely buy bulbs with A19 or A21 bases. Track and linear or tube lights come with pins or receptacles to use, which means a different base is necessary for those fixtures.


If you’re considering the A19 or A21 format only, you’ll have the following choices to consider.


Light Bulb Type

Why Use This Light Bulb Type

Standard LED Bulbs

The standard LED light bulb disperses light at wide angles throughout a room or outdoor space. It’s an ideal choice for hallways, reading lamps, and other common fixtures. You can use them for flush and semi-flush mount fixtures.

Flood LED Bulbs

This light bulb is designed to emit a more substantial and broader illumination profile to create light over a wide area. Its primarily used for outdoor needs, but it could serve some warehouses, stadiums, or stages.

Can LED Bulbs

You know this LED light bulb design better as a recessed lighting installation. The product fits into a specific socket, called a “can,” that’s mounted in the ceiling.

Candelabra LED Bulbs

Chandelier or candle bulbs are designed to look like a flame when installed in a fixture. It’s a decorative choice that works well in sconces, accent lighting installations, and decorative fixtures.

Globe LED Bulbs

This choice emits light in all directions. That’s why you see them installed in bathrooms or closets. They also serve people well when using them as pendant lights.

Vintage LED Bulbs

These light bulbs are sometimes referred to as “Edisons.” Their vintage look is all about the visual aesthetics of the product. Today’s designs use long, thin filaments that look like products from the past without compromising the light output levels you receive. They work well in industrial chandeliers or pendant lights.


When comparing A19 vs. A21 light bulbs, the primary difference is the size. You can find higher lumens options with a more extensive base, but the rest of the technology remains the same. The minor differences are not enough to prevent you from using either option in modern fixtures.


Choose the lumens you need, select the LED color temperature you want, and you’ll have a long-term solution for your lighting needs.​​​​

A21 and A19 Bulbs: What is the Difference?

There are several light bulb styles on the market, each denoted by a code. This code ensures that no matter the brand, you will always get the right shape and size of light bulbs. 

A21 and A19 bulbs are some of the most commonly used codes in domestic settings, and if you have ever wondered what the difference between them is, you are not alone.

In this article, we will take a deep dive into A19 and A21 light bulbs. So, keep reading to learn more about how they compare.

Table of Contents


What is the Difference Between A19 and A21 Bulb?

A19 and A21 are both type-A light bulbs of different sizes. A19 bulbs are 2.375 inches in diameter and 4.13 inches long. A21 bulbs are slightly larger, with a diameter of 2. 625 inches and a length of five inches.

What are Type-A Light Bulbs?

The type-A light bulb, also known as an A-shape or A-type light bulb, is a common household light bulb with a standard shape and screw base. The shape of the bulb is defined by a set of dimensions and guidelines established by the International Electrotechnical Commission (IEC). 

Generally, type-A bulbs are pear-shaped with spherical end sections narrowing down towards their E26 screw base. The type-A bulb is one of the most widely used bulb shapes and is commonly found in table lamps, floor lamps, and other household light fixtures. 

There are five A type bulbs commonly used in homes, including:

Bulb Size A15 A17 A19 A21 A23
Diameter 1.875″ 2.13″ 2.375″ 2.63″ 2.88″

Type-A bulbs are named for their diameter at their widest point in eighths of an inch. For example, an A19 bulb measures 19/8 inches, or 2.375 inches decimalized. 

A19 Bulbs vs A21 Bulbs

A19 bulbs are sometimes referred to as standard bulbs and are the most common type of light bulbs used in households. They are shaped like a pear and have a diameter of approximately 2.375 inches. A19 bulbs have a medium base (E26) and can be used in various household lighting applications.

An A21 bulb is so named because it has a diameter of 21-eighths of an inch or 2.625 inches. The A21 bulb is another common type of pear-shaped light bulb, and like the A19, many domestic light fixtures fit it.

What Types of A21 and A19 Bulbs Are Available?

There are many A19 and A21 light bulbs on the market, including clear, frosted, and coated. They can also be dimmable or non-dimmable, depending on the type of light fixture in which they are to be used.

In addition to these varieties, A21 and A19 bulbs are also available with different types of bulb technology, including incandescent, fluorescent, and LED bulbs.

Incandescent Bulbs

Incandescent bulbs are the traditional light bulb. They use a filament to produce light. The filament is made of a thin wire, usually tungsten, heated to a high temperature by an electric current. 

When the filament is heated, it produces light. Incandescent bulbs are relatively inexpensive and widely available, but they are not energy-efficient and have a short lifespan compared to other bulbs.

CFL Bulbs

CFL bulbs use a gas-filled tube to produce light. When an electric current passes through the gas, it emits ultraviolet (UV) light, which is then converted into visible light by a fluorescent coating on the inside of the tube. 

Fluorescent bulbs are more energy-efficient than incandescent bulbs and have a longer lifespan. However, they contain small amounts of toxic materials like mercury and take longer to reach full brightness.

LED Bulbs

LED bulbs work by using a semiconductor to produce light. When an electric current is applied, it emits light. The color of the light depends on the specific material used in the semiconductor.

LED bulbs are more energy-efficient and have a longer lifespan than other types of light bulbs because of the way they produce light. They give off very little wasted heat energy like incandescent bulbs, and unlike CFLs, they don’t need any warm-up time and reach maximum brightness instantly.

While A21 bulbs are a little bigger than A19’s, both should fit in most of the same lamps and light fixtures. This is me replacing my old burned out incandescent A19’s with new energy-saving LED bulbs.

It is also worth noting that LED bulbs are more durable than other types of light bulbs, too. This robustness is because they do not have a filament that can burn out or a gas-filled tube that can break. This quality makes them less prone to premature failure, increasing their expected lifespan.

Are A21 and A19 Bulbs Interchangeable?

Type-A bulbs like the A19 and A21 share the same E26 base type, which means that, mechanically speaking, they are interchangeable. However, due to the difference in their external dimensions, they may not fit into the same lighting fixtures. 

Do A19 and A21 Bulbs Offer the Same Performance?

The lighting performance of A21 and A19 bulbs depends on the specs of the specific light bulbs you are purchasing. However, both types can be bought with the same wattage and lumen ratings, meaning they should provide identical performance, with the only difference being physical size and shape.

However, A21 bulbs, because of their larger size, can dissipate heat more effectively than A19 bulbs and can therefore accommodate higher wattages. This means there are A21 bulbs on the market that exceed the lumen rating of the brightest A19 bulbs. 

Final Thoughts

There are many cases in which A19 and A21 bulbs are compatible and even interchangeable. Before changing an A19 bulb for an A21 or vice versa, be sure that the bulb wattage is suitable for the light fixture, and be sure that the bulb physically fits the enclosure.  

Finally, consider opting for LED bulbs instead of incandescent, halogen, or CFL. Provided that they are compatible with the wattage requirements of your lighting fixtures and have the same E26 base, A19 and A21 LED bulbs are interchangeable with other types of bulbs in those exact sizes.

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Philips LED bulb for only $5

Created on 05/07/2015 17:33
Author: Natali

It seems that there is a certain Moore’s law for LED lamps. Every year they are better, cheaper, lighter, more efficient…

Philips’ latest innovation: the company decided to create an LED lamp that is equivalent in brightness to a 60-watt incandescent lamp and sell it for only $4.97, making it the most the most affordable 60W equivalent LED light bulb on the market.

In the near future the company will pack the new light bulbs in a standard carton and start selling, and perhaps this will finally force people to move away from outdated and costly incandescent light bulbs. In the US alone, more than 70% of light bulbs are old, inefficient models.

The new Philips LED lamps consume only 8.5 watts and as an added bonus for consumers, the lamp will be sold in a special 2 for 1 package for 90 days starting May 1st.

Since energy-efficient lighting has become more affordable, a family of three has an average of 30 or more light bulbs, and lighting is used most often in areas of the home such as living rooms, kitchens and bedrooms. With the novelty from Philips LED and its attractive price, consumers will be able to use energy efficient LEDs throughout the home. In addition, Philips LED bulbs have a shatterproof design that makes them more attractive than other, less durable incandescent bulbs.

Over 10 years of use, each Philips 60W equivalent LED bulb saves about $62 compared to traditional incandescent bulbs.

In addition to the new light bulb, which has a heat output of 2700 k (warm white) and 800 lumens, a similar wattage lamp with a light temperature of 5000 k (daylight) and a 100 W equivalent lamp in size A19 will also be offered. . Unlike other 100W equivalent LED bulbs that are actually larger than A21, the new Philips lamp is fully equivalent to A19(100 W incandescent lamp).

Like previous Philips versions, the lamps do not have a heavy metal heatsink.

The only difference, aside from the price, is that the new light bulbs are not dimmable, and as a result, do not have a feature that the company calls “Warm Glow” – a technology that reduces the temperature of the glow when the brightness is reduced.

However, said Amy Huntington, President and CEO of Philips Lighting, “The new offering will allow LEDs to be more than just a luxury, but an affordable lighting solution that consumers can afford. It is a daily choice for quality, both for your home and for the environment.”

The new Philips LED lamps join the company’s industry-leading portfolio, which also includes Philips Hue, the world’s most advanced connected lighting system.

Facepla.net based on: newscenter.philips. com

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Our online store offers different types of light bulbs with different wattages to better meet your needs. Our Type A incandescent bulbs are high performance, energy saving and easy to install; Nbsp;

bulb type

2W A15 bulb / 25W Edison A15

2w customizable A15 LED bulbs equivalent to 25w can supply 200k – 600k CCT.

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4W A15 bulb / 40W Edison A15

4W A15 tunable bulb equivalent to 40w provides clear glass, white glass, frosted glass and amber glass.

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5.5 bulb in watts – a115 / 60 W 15

5.5W adjusts the light to 60W equivalent A15 retrograde lamp, which is the most sold A15 and can be used for E12 and E26 holes.

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8W A15 Incandescent / 75 Watt Edison A15

8W can adjust the light of a retro A15 lamp, equivalent to 75w, Lumen output 800lm. clear glass, white glass, frosted glass, amber glass.

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4W A19 Incandescent / 40W Edison A19

The 4W A19 is tunable with modern 40w equivalent bulbs that provide clear glass, white glass, frosted glass, amber, silver top glass.

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7W A19 incandescent bulb / 60W Edison a19

7W A19 can dim a retrograde lamp equivalent to 60w, 2200K – 6500K CCT, clear glass, white glass, frosted glass, amber color, silver top glass.

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8W A19 incandescent bulb / 75 watt Edison a19


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8W A21 incandescent / 75 watt Edison A21

8W A21 tunes modern lamps equivalent to 75w, 2200K – 6500K CCT, clear glass, white glass, frosted glass, amber color, silver top glass.

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12 W A21 incandescent / 100 W Edison A21

12W A21 tunable for modern 100w equivalent lamps, 2200K – 6500K CCT, clear glass, white glass, frosted glass, amber color, silver top glass.

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15W A23 Incandescent / 150W Edison A23

15W A23 can dim retrograde lamps equivalent to 150w, 2200K – 6500K CCT, clear glass, white glass, frosted glass, amber color, silver top glass.

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answer to question


what is the size of type A lamp?

Edison bulb type a means classic pear lamp with Edison screw base. since the beginning of the twentieth century, this light bulb has been the most popular in everyday life. the most commonly used type of a series lamp is the 60 lamp (or USC A19 equivalent).) with a diameter of 60 mm (19/8 inch or 2/3/8 inch) in the widest range.