Match the old bulb’s base, and stay within the watts on the lamp’s label. Feit makes a 15 watt C7 on the small E12 base for salt lamps, and lists its 40 watt T8 on the E17 base for them too.
E12 or E17
The two bulbs Feit lists for salt lamps have different bases, so check which one the old bulb has. E12 is the small candelabra screw base, and E17 the intermediate one, between E12 and the standard E26.
Feit Electric’s bulbs for salt lamps, from its product pages
Bulb
Shape
Base
Watts
Lumens
BP15C71/2
C7, 7/8" across
E12
15
100
BP40T8N/HDRP
T8 tube, 1" across
E17
40
360
Both are incandescent and dimmable.
Feit describes the 15 watt C7’s E12 base as fitting most standard salt lamps. It lists the 40 watt T8 for microwaves, refrigerators and lighted cabinets as well as salt lamps.
Watts
Keep to the old bulb’s watts, and never go over the most watts on the lamp’s label or in its instructions. A bulb of higher wattage than recommended may overheat the fixture, its wiring or things nearby.
Unplug the salt lamp and wait for the bulb to cool before you take it out.
The bulbs come from Feit Electric’s product pages, the base and shape sizes from the bulb makers’ size guides, and the wattage rule from the CPSC. Checked against published data from Feit Electric, GE Lighting, CPSC and Westinghouse.
See all 5 sources
GE Lighting, “A Guide to Light Bulb Sizes, Types, Shapes, and Codes” (2022)
Feit Electric, “Decoding Bulb Shapes and Sizes” (2017)
US Consumer Product Safety Commission, Home Electrical Safety Checklist (Pub 513): bulb wattage for the fixture
Westinghouse Lighting, “Bulb Size” guide, and lamp catalog: shape sizes in eighths of an inch
Feit Electric product pages: wax warmer and salt lamp bulbs (BP15C71/2, 15 W C7 E12; BP20G121/2, 20 W G12-1/2 E12; BP40T8N, 40 W T8 E17)
General guidance from manufacturer and standards data. Products vary, so check the label and the maker's instructions.