Screwdrivers come in many different sizes. As well as the standard large, medium and small, there are also stubby screwdrivers that are ideal for use in tight or confined spaces. The tip width and the length of both the blade and the overall tool are usually measured in millimetres (mm).
You should note that some sorts and brands may offer different sizing options to others. For instance, there are four standard Phillips screwdriver sizes. These range from #0 to #4, where #0 is the smallest screwdriver.
Some tools can also be classified by torx size. This is shown by the letter T followed by a number - for example, T10 screwdrivers. It ranges from miniature screwdrivers right up to T45 and beyond. This system can also be applied to screws, helping you choose the corresponding screwdriver for a particular sized screw.