A19 vs. A21: What Bulb Size is Better?

FACTS CHECKED BY  Bob Smith

A19 vs. A21 are popular LED bulb sizes you can see in any hardware store. But, there’s a high chance that you can’t tell them apart.

In truth, it’s easy to think A19 and A21 bulbs are interchangeable. However, that’s a false assumption. Don’t worry if you don’t know the differences between these sizes.

Luckily, we’ve prepared this guide to help you see a head-to-head comparison of A19 vs. A21.

Are you ready? Let’s jump in!

What are A19 and A21 Bulbs?

A19 and A21 bulbs

A19 and A21 bulbs

Different Bulb Codes Meaning

Pear-shaped LED

Pear-shaped LED

First, we have the A group that consists of A15, A19, A21, and A25. 

These arbitrary bulbs are commonly used as porch light fixtures, ceiling, and closet lights. Further, the numbers in each code describe the bulb’s diameter in one-eighth of an inch.

  • A19 – 19/8 = 2-3/8” diameter
  • A21 – 21/8 = 2-5/8” diameter
  • A25 – 25/8 = 3-1/8” diameter
  • A15 – 15/8 = 1-7/8” diameter

Also, the most common base type for these bulbs is the E26/E27 medium screw base.

Second is the B and C groups. These bulbs have conical shapes and are often called candle bulbs. Additionally, you can use these bulbs for decorative home lighting applications. And this group consists of B10, CA10, C9, C15, and C19. This bulb group’s most common base type includes E26/E27 medium screw base, E12 candelabra, and E17.

Third, we have the G group, which includes G30, G14, G25/G80, G11, G16/G50, and G60. This group consists of bulbs with full and round shapes in different sizes. And they are useful for applications like ornamental fixtures, foyer lights, etc.

G30 is the most common bulb in this group. And you can use them in makeup vanities and bathrooms. Further, the common base type in this group is E12 candelabra and E26/27 medium screw base.

A19 vs. A21 Light Bulb: What’s the Difference?

Standard LED bulb

Standard LED bulb

Let’s compare these bulbs to pick out the differences:

The Size

Although they have similar pear shapes, these bulbs have different sizes. An A19 has about 2.375 inches in diameter, while the A21 features a 2.625 inches diameter.

Color Temperature

A19 and A21 bulbs feature various color temperatures ranging from warm to cold. And we can measure the color temperature in CCT. So, A19 bulbs with a 2,700k CCT rating emit warmer colors. At the same time, A21 with 4,000k or more produces crisper light.

Lifespan

The A19 and A21 bulbs will offer anywhere between 20,000 to 30,000 hours.

Some versions come with dusk to dawn sensors. So, they go off during the daytime and light up at night, helping to increase lifespan and efficiency.

Cost

A19 and A21 LEDs are more expensive than more traditional options. However, the A21 costs a few dollars more than an A19 bulb.

Applications

A21 bulbs have larger surface areas, making them functional in ceiling lamp fixtures and larger rooms. At the same time, A19 bulbs work better for floor and table lamps since they have smaller sizes.

A19 vs. A21: Comparison Chart

FactorA19 LED BulbA21 LED Bulb
LumensUp to 1,000Up to 1,600
Height4.13 inches5 inches
ApplicationsSmall rooms, floor, and table lampsWider spaces
Base typeStandard E26 screw-inStandard E26 screw-in
Diameter2.375 inches2.625 inches
Life span25,000 to 30,000 hours25,000 to 30,000 hours
CCT2,700K2,700K to 4,000K
Watts11W14W

A19 vs. A21: Pros and Cons

Two A19 LED bulbs

Two A19 LED bulbs

Here are some advantages and disadvantages of A19 and A21 bulbs.

A19

Pros

  • A19 offers warmer lighting that can give a cozy feeling.
  • Some A19 bulbs manufacturers may give a warranty of up to ten years.
  • A19 LEDs are energy efficient, costing only $1.20 annually (based on an average of 3 hours of usage per day).

Cons

  • These bulbs may not be big enough to illuminate an entire space.

A21

Pros

  • A21 LEDs use 90% less energy than their traditional counterparts.
  • They offer better value for money.
  • You can get additional lumens with A21 bulbs, giving your space more illumination.

Cons

  • A21 bulbs may not fit all fixtures because of their size.

Are A19 and A21 Bulbs Interchangeable?

Glowing A19 bulb

Glowing A19 bulb

In truth, A19 and A21 bulbs have similar E26 bases, making it possible to swap them at will. However, the shape and size of the fixtures may cause some issues.

While A19 bulbs can easily fit in fixtures designed for A21 lights, the reverse can’t happen because A21 bulbs may be larger than fixtures designed for A19 lights.

However, although they’re interchangeable, A19 and A21 don’t produce the same results. And their size differences are not for aesthetic purposes only. Due to their bigger sizes, A21 lights use higher wattages and generate more lumens.

Is A19 a Standard Bulb Size?

The A19 has been a bulb standard for many years. In truth, most manufacturers design their bulbs to meet the width and height of the A19.

So, the A19 is your go-to if you want a new bulb set that works with various home fixtures. And they don’t need any modifications to be adequate replacements.

Is A21 a Standard Bulb Size?

A21 bulbs are wider than the bulb standard. So, you might face problems fitting one into a smaller fixture.

These bulbs need special fixtures to accommodate their large sizes. Though they don’t use the standard bulb size, A21 offers brighter lighting than A19. So, they’re great choices if you’re willing to make modifications for extra illumination.

Rounding Up

There are numerous similarities with the A19 vs. A21 comparison. And since there’s nothing unique about their designs, you’ll need more than visuals to make a choice.

So, depending on your application, we can’t say which is better. For instance, if you have table lamps, floor lamps, or a small space, then A19 would be your go-to.

Contrarily, if you’re looking to illuminate larger rooms, you might benefit from the extra lumens of A21 bulbs. Also, we recommend checking your light fixture thoroughly before swapping from A19 to A21.

Do you have any questions? Feel free to contact us, and we’ll be happy to help.

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