Guide 01 · Bulbs
Two separate decisions. Shape is how it looks. Base is whether it threads in at all. Pick the look first, then verify the socket before you buy.
Choose a shape for the fixture
If the bulb is visible, it's part of the design. If it's hidden behind a shade, shape barely matters.
- A19 — the everyday bulb. Shaded fixtures and table lamps.
- ST64 — Edison style. Long tapered glass, made to be seen. Exposed sockets.
- G25 — globe. Vanity bars and exposed fixtures.
- B11 — candle. The flame shape used in most chandeliers.
- BR30 — flood. Recessed cans.
Then match the base to the socket
"E" means Edison screw. The number is roughly the base diameter in millimeters.
- E26 — medium. The standard lamp socket in North America.
- E12 — candelabra. What most chandeliers take.
- E17 — intermediate. Specialty fixtures, appliance bulbs.
- GU10 — twist-lock, two pins. Spotlights.
- G9 — bi-pin. Compact modern fixtures.
Theo's exposed-bulb rule
If you can see the bulb, make it part of the design — ST64 Edison, G25 globe, or B11 candle. Vintage-looking bulbs can still be efficient LEDs. Check base, voltage, size, and the fixture's wattage rating before you buy.
Before you buy
Shape does not guarantee base size. Match base, shape, voltage, and the fixture's maximum wattage. Measure when unsure, and never force a bulb into a socket.