five a19 bulbs with the fourth one turned on and the words A19? pointing to the turned on one

A19 light bulbs are a popular option on the market for a good reason; they come in a standard household shape compatible with most lighting fixtures.

Initially, A19 light bulbs used incandescent technology in which the wire filament is heated until it glows. However, technological advancement has resulted in LED A19 light bulbs, an energy-efficient option.

This article will discuss the naming of A19 light bulbs, their dimensions, and their lighting properties. We’ll also cover LED A19 light bulb alternatives to help you understand the differences and choose the best.

Let’s delve in!

What Are A19 Light Bulbs?

A19 light bulbs are the standard bulbs commonly used in household lighting fixtures. These bulbs have a pear-like shape with a base size of E26 and a diameter of approximately 2.4 inches (60mm).

a graphic of an A19 LED light bulb with two arrows pointing to it showing dimensions of 2.4 inches wide and socket base type E26

The Naming of A19 Light Bulbs

Lighting terminologies can be confusing if you’re new in the industry. The fact is that light bulbs like the A19 version have coded names with different meanings.

At this point, you may be wondering where the code “A19” came from and why the letter “A” and the number “19.”

The International Electrotechnical Commission (IEC) is in charge of standardizing the naming system for light bulbs. The commission standardizes the naming codes based on shape and size. The naming incorporates a letter for the form and a number for the size. 

The term “A19” comes from the bulb’s shape and size. The letter “A” in this name stands for “Arbitrary,” a familiar shape to most of us. Usually, these are the standard bulbs that take the shape of an upside-down pear, as shown below.

a hand in the middle of the picture holding up a lit up LED light bulb with a garden in the background

The second part of the name is the two-digit number “19.” This number indicates the bulb’s center diameter in eighths of an inch. The number accounts for the center diameter since it’s the widest point of the bulb.

The A19 is the standard, pear-shaped bulb with a diameter of approximately 2.375 (19/8) inches (60mm). You can confirm this length by measuring the bulb’s center width in inches and dividing the result by eight.

A19 Dimensions

When shopping for a light bulb, you want to choose an option that fits your needs. In other words, you need a bulb compatible with your lighting fixture and cast. This compatiblity means understanding the bulb’s dimensions before making any purchase.

A19 bulbs come in specific dimensions based on wattage and voltage. As mentioned earlier, they have a base size of E26 with a diameter of 2.4 (19/8) inches in the US.

A19 bulbs are called A60 in countries that use the metric system. In this case, the name results from converting the 2.4-inch diameter into millimeters to get 60.

Since A19 light bulbs are standardized, they are compatible with most household lighting fixtures. Here are the top energy-efficient fixtures you can use in your home.

According to the ANSI C79.1 standards that govern A19 bulb dimensions in North America, the bulbs’ length varies from 3.9 (99.06mm) to 4.3 inches (109.22mm).

The table below compares the dimensions of A19 light bulbs with different wattages:

Bulb WattageMaximum Length (mm)Maximum Diameter (mm)
40W type 21010869.0
40W type 211112.769.5
50W type 20610068.0
50W type 211112.769.5

Table 1: A19 light bulb dimensions

Here is a video to guide you in measuring the dimensions of an A19 light bulb:

Screnshot from a video to guide you in measuring the dimensions of an A19 light bulb
Courtesy of AMRE Supply

A19 Light Bulb Properties 

Lighting properties are a crucial consideration when buying a light bulb. These metrics determine the bulb’s aspects, such as:

  • Brightness – the amount of light the bulb emits in lumens.
  • Color Rendering Index (CRI – the bulb’s ability to reproduce the accurate color of the object it illuminates on a scale of 0 to 100. A bulb with 0 CRI illuminates objects with the same color. On the other hand, a 100 CRI bulb reproduces the object’s true colors. Incandescent and halogen A19  bulbs have a CRI of 100.
  • Color temperature – determines whether the emitted light is cool or warm.
  • Beam angle – the angle of light emission.

A19 light bulbs are omnidirectional; they distribute light evenly over the entire heat sink surface.

The omnidirectional property is responsible for the 360-degree beam angle in A19 bulbs. You don’t have to worry about light distribution with such an angle. Once fixed, the bulb emits light in all directions to cover a large area.

The bulb’s wattage determines its brightness; the more watts, the more the brightness. For instance, while a 60W A19 incandescent bulb emits 800 lumens of brightness, its 40W counterparts emit 450 lumens. Thus, if you want more shine, go for a high-wattage A19 light bulb.

The Evolution of A19 Bulbs

Light bulbs have come a long way since their invention in the 18th century.

Arc lamps were the first artificial lighting source that used electricity to create an arc of light. However, the source was unsuitable for household use due to its size, shape, and high energy consumption.

Thankfully, technological advancement has significantly improved the quality of artificial lighting sources over time. These technological advancements led to the invention of A19 light bulbs, a more advanced and energy-efficient light source.

As with any technology, A19 bulbs have changed over the years to enhance efficiency. Today, the A19 bulb you buy from any store differs from the one used decades ago in terms of brightness, wattage, and energy efficiency.

A19 light bulbs went through the following evolution stages to attain their current status:

Incandescent A19 Light Bulbs

These were the first types of A19 bulbs based on the principle of incandescence. According to this principle, a light bulb emits light when an electrical current passes through and heats a wire filament.

Incandescent A19 bulbs use a wire filament made of tungsten. The wire is heated until it glows to emit visible light. Besides having a high melting point of up to 3,422°C (6,191.6°F), tungsten doesn’t oxidize. These properties make it suitable as a wire filament in incandescent bulbs.

A glowing A19 light bulb hanging from a fixture trasnsposed against a dark background

The wire filament produces tiny particles as it continues burning. With time, the bulb burns out when no more particles are left to burn. Usually, you can expect your incandescent A19 bulb to burn out after 800 to 1,200 hours of life

It’s worth mentioning that incandescent A19 light bulbs are not the most energy-efficient option. According to Materials Research Science and Engineering Centers, these bulbs produce up to 90% of their energy as heat rather than light. Unfortunately, this makes them expensive to use in your home.

Moreover, these bulbs have a shorter lifespan. As mentioned, they can last between 800 and 1,200 hours before burning out. When that happens, you’ll have to buy a new bulb or risk being left in the dark.

Halogen A19 Light Bulbs

These are incandescent bulbs whose filament is enclosed in a small quartz envelope containing iodine and bromine gasses. The gas helps evaporate and redeposit tungsten particles onto the burning filament, thus extending its lifespan.

This process increases the light bulb’s efficiency and reduces the energy consumed. Halogen A19 bulbs consume up to 28% less energy than their traditional incandescent counterparts. They also produce more light for the same amount of energy due to the impact of halogen gas.

Due to the high temperature required in halogen bulbs, they are usually made of quartz instead of glass. Quartz is highly resistant to temperature and can last many years without breaking or cracking.

More often than not, halogen light bulbs last up to three times longer than traditional incandescent ones. Therefore, you can expect them to serve you for up to 3,000 hours before needing a replacement. However, halogen A19 light bulbs are still not the most energy-efficient option available today—they consume more energy than LED light bulbs.

Compact Fluorescent A19 Lights

Compact fluorescent lights (CFL) are a more advanced and energy-efficient alternative to incandescent and halogen bulbs.

Instead of heating a filament, as with incandescent light bulbs, CFL bulbs rely on argon and mercury vapor for lighting. These bulbs pass an electric current through the vapor to produce ultraviolet (UV) light. The white phosphor coating inside the bulb converts this UV light into visible light.

A CFL bulb stacked on a pile of cash and coins, indicating the savings provided by using this energy-efficient light bulb

The use of UV light gives CFL A19 bulbs a lighting efficiency ranging between 7-10%. In comparison, incandescent A19 light bulbs have a lighting efficiency ranging between 1.5 and 2.5%.

Finally, CFL A19 lights have a longer lifespan, with each bulb lasting about 8,000 hours.

Expert Tip: Since CFL bulbs contain mercury, they are unsafe for disposal in regular trash. It would be best to dispose of them appropriately by taking them to an authorized disposal center. Alternatively, you can check with your local waste management company for disposal instructions.

LED A19 Light Bulbs

LED (Light Emitting Diode) is the latest generation of A19 light bulbs.

The principle of electroluminescence is the basis behind the operation of LED A19 light bulbs. According to this principle, a bulb produces light when an electrical current passes through a semiconductor material.

LED A19 light bulbs use a p-n junction diode that emits light when a voltage is applied. They also use light-emitting phosphors that produce more intense light for the same energy.

The electroluminescence principle and the microchip-based design make LED A19 light bulbs more energy-efficient than their halogen and incandescent counterparts.

According to Energy Star, LED light bulbs are 90% more efficient. Since lighting accounts for nearly 20% of household electricity consumption, this is a massive benefit to your pocketbook.

What’s more, LED A19 bulbs last up to 25 times longer than traditional incandescent ones. Consequently, you can expect them to serve you up to 25,000 hours.

On the downside, LED A19 light bulbs cost slightly more than their halogen counterparts. However, their long lifespan and energy efficiency make them a worthwhile investment. 

Check out this article for ways to tell if a light bulb is energy-efficient.


A19 light bulbs are the standard household bulbs used in lighting fixtures. You can opt for an incandescent A19 bulb or the advanced LED option.

LED A19 light bulbs are the most energy-efficient and long-lasting variety. Therefore, they are your go-to option to reduce energy bills or replace bulbs less frequently.

Leave a Reply

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