A19 Bulb
The standard household light bulb shape — a pear-shaped bulb 2.375 inches in diameter, used in most lamps and fixtures.
When someone says "light bulb," they're picturing an A19. It's the default shape that fits the vast majority of household lamps, ceiling fixtures, and porch lights. The "A" stands for arbitrary (the original shape designation), and "19" means 19 eighths of an inch in diameter — about 2.375 inches or 60mm.
A19 bulbs almost always use an E26 base in North America or E27 in Europe. They're available in every color temperature, CRI level, and wattage equivalent you could want. If you're replacing a standard bulb and aren't sure what shape you need, it's almost certainly an A19.
The main thing to watch is physical fit. Some enclosed fixtures have tight openings where a slightly longer LED A19 might not fit — LED versions can be a few millimeters longer than the incandescent originals due to the heat sink and driver housing.
Specifications
| Shape | Pear / arbitrary |
| Diameter | 2.375 in (60mm) |
| Common base | E26 (US) / E27 (EU) |
Related Terms
- A21 Bulb
A slightly larger version of the standard A19 bulb — 2.625 inches in diameter. Used for higher-wattage LED bulbs that need more space for heat dissipation.
- E26 / E27 Base
The standard Edison screw base used in most household lamps and fixtures. E26 (26mm) is the North American version, E27 (27mm) is the European equivalent.
Mentioned in
What Is The Difference Between A19 And A21 Light Bulbs?
An A21 won't always fit where an A19 lived — the extra width and length can press against a tight fixture, turning a simple swap into a fire-safety problem.
What Is An E26 Bulb?
A19 and E26 aren't two names for the same thing — one describes the bulb's shape, the other its base, measured in completely different units on the same bulb.
Can LED Lights Make Speakers Buzz? 3 Reasons + Fix
Your LED bulb isn't broadcasting radio waves — but its driver switches on and off up to two million times per second, which is squarely inside the AM band.
Can LED Lights Power Solar Panels?
Fifteen minutes of direct sunlight delivers as much energy to a solar watch as 8–10 hours under an LED bulb. Even heavy cloud cover usually beats an indoor light.
Can You Touch LED Bulbs With Your Hands?
Touching an LED bulb with bare hands is fine — it's halogen bulbs where skin oils trigger devitrification, crystallizing the quartz envelope until it cracks under heat.
Can I Use LED Bulb In Wax Warmers?
LEDs actually run hot — they just send that heat out the base, away from the wax dish. That's the exact opposite of what a warmer needs.