What bulb base does a floor lamp take?
Most floor lamps use an E26 medium screw base. European-made lamps may use E27, which fits the same socket in most cases.
Most common answer
The E26 medium screw base is the standard for floor lamps sold in North America. It is a 26 mm threaded base and accepts the majority of A19, A21, and decorative bulbs available at hardware stores.
If your lamp was purchased in Europe or carries a European brand, it likely uses E27 (27 mm thread). The two are dimensionally close enough that many bulbs will physically fit either socket, though voltage ratings differ — always check the lamp's wattage plate before substituting.
How to confirm your socket type
- Unplug the lamp and let the bulb cool completely.
- Remove the shade and look inside the socket shell — many sockets have a label stamped on the brass or aluminium shell: E26, E27, or a wattage rating.
- If there is no label, measure the thread diameter of the existing bulb base with a ruler. 26 mm ≈ E26; 27 mm ≈ E27.
Mogul-base exception
A small number of large torchiere-style floor lamps use an E39 mogul base, designed for high-wattage halogen or metal halide lamps. If your socket is noticeably larger than a standard bulb base, check the lamp's rating plate — it will specify E39 or 300 W+.
Bulb shape compatibility
With an E26 base confirmed, choose a bulb shape that fits your shade:
- A19 — standard, fits most opaque and drum shades
- A21 — slightly larger, good for open-top torchieres needing more light output
- G25 — globe shape for decorative transparent shades
See the bulb shape reference for dimensions.