most common form factor of light bulb

A-series light bulb - Wikipedia
The A-series light bulb is the "classic" glass light bulb shape that has been the most commonly used type for general lighting service (GLS) applications since the early 20th century. It has … Wikipedia
🌐
Wikipedia
en.wikipedia.org › wiki › A-series_light_bulb
A-series light bulb - Wikipedia
December 3, 2025 - 110 mm (4+3⁄8 in) in length. Other sizes with a data sheet in IEC 60064 are A50, A55, A67, A68, A71, A75, and A80. Another common A-series light bulb type is the A15 bulb which is commonly used in the US for appliances and ceiling fans.
🌐
Commercial LED Lights
commercialledlights.com › home › types of light bulbs
Types of Light Bulbs | What You Need To Know
December 11, 2023 - A15 Light Bulb – An A15 light ... “A” stands for Arbitrary (or Classic) shape, and “15” indicates its diameter in eighths of an inch....
People also ask

What is an A19 bulb?

When picturing the shape of a light bulb, the A19 usually comes to mind. You may see it referred to as an upside-down pear-shaped bulb. Though A19 bulbs were originally designed for incandescent technology, you can now find a wide selection of LED versions that function at a much lower wattage. This means they consume much less power!

They often use a standard screw base, the E26 base. The E26 base, also known as the medium base, works in most residential applications. Less commonly, you may find A19 light bulbs that use an E12 candelabra or GU24 pin base. The candelabra base also works as a screw-type base but features a smaller diameter than the E26.

The number next to the ‘A’ refers to the diameter of the bulb in 1/8 of an inch so as that number increases, so does the size of the bulb.

  • This means an A19 bulb measures 19/8 or around 2.375 inches in diameter.
  • An A15 should measure around 15/8 or 1.875 inches.
  • An A21 measures around 2.625 inches around.

To learn more, check out our buying guide The Anatomy of the LED Light Bulb!

🌐
homelectrical.com
homelectrical.com › shop by brands › sylvania led light & fixture - ledvance › sylvania light bulb & lamp › sylvania bulb: a15, a21, a19 lamp
Shop Sylvania Bulb: A15, A21, A19 Lamp | HomElectrical.com
Where can I use a Sylvania A19 bulb?

Use LEDVANCE Sylvania bulbs anywhere from commercial offices and restaurants to residential kitchens, living rooms, and bathroom spaces. You can use them in desk lamps, porch lights, wall sconces and most household lighting fixtures.

Want to replace that old 60W incandescent in your desk lamp? Why not try an 8.5 watt Sylvania A19 lamp?

Need a festive bulb for the holidays? Maybe you want a fun color to change up your fixtures? LEDVANCE Sylvania offers a colorful line of A19 LED bulbs, like this 8.5W green bulb, that are suitable for damp locations.

🌐
homelectrical.com
homelectrical.com › shop by brands › sylvania led light & fixture - ledvance › sylvania light bulb & lamp › sylvania bulb: a15, a21, a19 lamp
Shop Sylvania Bulb: A15, A21, A19 Lamp | HomElectrical.com
🌐
GE Lighting
gelighting.com › inform › guide-light-bulb-sizes-types-shapes-and-codes
A Guide to Light Bulb Sizes, Types, Shapes, and Codes.
The numbers of the bulb indicate ... indicates that the bulb is 19/8ths inches in size. Similarly, A15 bulbs are smaller than A19 bulbs, though both fit in the standard household light bulb base (E26)....
🌐
Amazon
amazon.ca › wattage-Incandescent-Replacement-Non-Dimmable-Bathroom › dp › B088PH8Y9B
Low wattage A15 LED Light Bulb Replacement 15W 20W 25W E26 Base 120V 2W 150lm Soft White 2700K Non-Dimmable for Bathroom, Bedroom, Bedside Accent Lamps Pack of 4, LED Bulbs - Amazon Canada
Low wattage 2W 150lm dim light LED bulb will be an replacement for A15 15 watt to 25 watt incandescent bulb, standard E26 screw base, widely used in bathroom, bedroom for nightlight, bedside lamp, accent lamp table lamp mood lighting pendant ...
🌐
PartyLights
partylights.com › home › bulbs only › incandescent bulbs › a15 bulb (medium/e26 base)
A15 Medium Base Bulb - Clear & Colors | E26/ Medium Base Replacement
A15 Bulb (medium/E26 base)
A15 (15 watt) replacement bulbs are one of our most popular bulbs for commercial medium base string lights. Available in a variety of colors, these classic shape replacement bulbs always look great!CASES ship in 3-5 business days. TYPE: Incandescent A15 clear bulbs SIZE: 2” in diameter (3.5” high with base) with medium/E26 base MATERIAL: Glass WATTAGE: 15 watts each DIMMABLE: Yes (dimmers sold separately) AVERAGE LIFE: 5,000 hours Product Details: For indoor or outdoor use. Compatible with any of our medium/E26 base cords.
Price   US$1.30
🌐
Sunco Lighting
sunco.com › products › a15-led-bulbs
A15 LED Bulb, 800 Lumens
A15 LED Bulb, 800 Lumens
Compact LED for refrigerators or fans. Withstands temperature as low as 4°F.
Price   US$1.99
🌐
LightBulbs
lightbulbs.com › led bulbs / lighting › led light bulbs › led a-line / pear / tube
A15 LED Light Bulbs | LightBulbs.com
Of all the A-shaped bulbs, the A15 has the smallest diameter. Due to its smaller size, the A15 is often used in signs and decorative lighting.
Find elsewhere
🌐
HomElectrical
homelectrical.com › shop by brands › sylvania led light & fixture - ledvance › sylvania light bulb & lamp › sylvania bulb: a15, a21, a19 lamp
Shop Sylvania Bulb: A15, A21, A19 Lamp | HomElectrical.com
The candelabra base also works ... bulb. This means an A19 bulb measures 19/8 or around 2.375 inches in diameter. An A15 should measure around 15/8 or 1.875 inches....
🌐
Lohas LED
lohas-led.com › art › one-thing-you-should-know-about-led-light-bulbs.html
One thing you should know about LED light bulbs
An A15 bulb, therefore, has a diameter of 15 divided by 8 inches, or approximately 1.9 inches. reference:https://en.Wikipedia.org/wiki/A-series_light_bulb Type E bulbs Such as E26/E27, the letter E before a number indicates it's an Edison bulb. The Edison screw fitting is a system of screw ...
🌐
DYR
normanlamps.com › home › a-type light bulbs
A-Type Light Bulbs - A15, A19, A21, A23 Bulbs | Norman Lamps
The most common is the A19, measuring 19/8 inches (approximately 2.375 inches) in diameter, which has become the standard household bulb size. Smaller A15 bulbs, at 15/8 inches in diameter, work perfectly in applications where space is limited, such as ceiling fan light kits, small table lamps, ...
🌐
Reddit
reddit.com › r/homeimprovement › anyone know anything about light bulb sizes?
r/HomeImprovement on Reddit: Anyone know anything about light bulb sizes?
January 14, 2024 -

My mom has an old ceiling fan that we're trying to find replacement white bulbs for. She bought a couple of packs of bulbs and the base was too small. The pack says they are A15. Does the 15 mean 15mm diameter of the base? That's what I thought, but I measure 10mm and the pack is sealed. Either the 15 doesn't mean what I think it means or the bulbs were packaged wrong from the manufacturer. I took one bulb out of the fan and it actually measures 15mm diameter for the base. I'm lost on what bulb to order.

🌐
CPS LIGHTING
cps-lighting.com › home › enterprise blogs › a15 bulb guide: everything you need to know
A15 Bulb Guide: Everything You Need to Know
October 2, 2024 - A15 bulbs are about 2.5 inches in diameter. They are perfect for small appliances like refrigerators and ovens. They usually come with the standard E26 base, which is the same as the A19 bulb.
🌐
DYR
normanlamps.com › home › a-type leds
A-Type LEDs - LED A21, A19, and A15 sizes available from NLI
A15 bulbs at 15/8 inches (1.875 inches) are more compact, commonly used in ceiling fans, smaller fixtures, and appliances where the standard A19 would be too large or visually overwhelming. The energy savings with A-Type LEDs are substantial and measurable. A typical 9-watt A19 LED produces ...
🌐
Multilighting
multilighting.ca › home › light bulb › led light bulb › bulb a15 3000k
Bulb A15 3000K | Eglo | White | Multi Lighting
- LED Bulb, 5.5W, 3000K, 450 Lumens, 25000 Hours. - Socket E26. - Shape A15. - Dimmable with an regular or universal dimmer. - White finish. - Opal glass. - 3 years warranty.
🌐
Homedepot.ca
homedepot.ca › lighting & ceiling fans › light bulbs › led bulbs
A15 Led Light Bulbs: Smart, Dimmable & More - Homedepot.ca
Lighting & Ceiling Fans Light Bulbs A19 (468) BR30 (89) PAR38 (85) B11 (85) T8 (82) ST19 (76) PAR20 (72) A21 (60) GU10 (60) G25 (54) MR16 (43) A15 (38) B10 (37) PAR16 (37) G9 (28) PAR30 (27) T4 (21) Corn Cob (19) T12 (17) T10 (17) PAR30 Short Neck (15) BR40 (15) T5 (14) G16.5 (13) G4 (12) T3 (12) T6 (10) MR11 (9) R20 (9) C7 (8) G40 (7) PL (6) BA11 (6) S14 (5) G8 (4) A23 (4) ST45 (3) T9 (3) S11 (2) ST64 (2) GY8.6 (2) GU24 (2) T14 (2) A35 (2) A40 (2) ST15 (2) G63 (1) R14 (1) T140 (1) 8809561883232 (1) ST20 (1) E12 (4) E26 (34) A-Line (24) Spiral (6) Corn Cob (4) Vintage Edison (2) Candelabra (1)
🌐
Quora
quora.com › What-is-an-A15-bulb-base
What is an A15 bulb base? - Quora
Answer: A15 refers to the bulb envelope. A is the pear shaped envelope and the number 15 refers to the diameter in 1/8th inch. The standard Edison screw base is referred to as an E26.
🌐
HomElectrical
homelectrical.com › led lights & light fixtures › led bulbs › a15 bulbs
Shop A15 Bulbs | HomElectrical.com
LED bulbs categorized as A light bulbs are some of the most widely used lighting solutions. The letter stands for standard household/ arbitrary as they are commonly used for most household fixtures. The number 15 on A15 light bulbs indicates the bulb has a size of 1-7/8th in.
🌐
Amazon
amazon.com › ask › questions › Tx28OBP6V3GPKDZ
Amazon.com: Customer Questions & Answers
A15 bulbs are usually recommended in a close quarters area, maybe on a small lamp or something. The last thing you want is the lamp shade to catch fire. ... I would have to say no. An A15 is a medium size for appliances and the bulb part is aprox 2.25 inches from the metal base.
🌐
Cymakcanada
cymakcanada.ca › blogs › news › are-a15-and-a19-bulbs-interchangeable
Are A15 and A19 Bulbs Interchangeable ? – www.cymakled.ca
Getting the answer to “Are A15 and A19 bulbs interchangeable” can be helpful in increasing the ambiance of any space. A15 and A19 bulbs can be interchangeable in some situations, mainly when they have the same base and wattage. However, you must be mindful of the differences in size and light ...