A screwdriver is a tool used to tighten or remove screws. Screwdrivers are identified by the kind of screws they fit. The commonest types of screwdrivers are the slotted (also known as straight-edge, flat, or standard tip) and the Phillips head. More specialized varieties include:
| Some types of screw
A screwdriver is most effective when the width of its head matches the width of the slot in the head of the screw. Among the most generally useful screwdrivers are a quarter-inch slotted and a number two Phillips head. However, it is a good idea to have a complete set of screwdrivers to match the variety of jobs can crop up around the home and elsewhere.