Light bulbs having an E27 base will fit most basic lighting fixtures. In the United States, most light bulbs are built with an E26 base, while European light bulbs are more commonly manufactured with an E27. Despite having slightly different base widths, E26 and E27 bulbs are generally interchangeable.
E27 light bulbs have a 27mm base, and E26 light bulbs have a 26mm base. Both will fit in most standard light fixtures. The difference between the two types of bulbs is that E27 light bulbs are rated for use with up to 240 volts, whereas E26 light bulbs are only rated to be used with up to 120 volts.