Buying guide to electric screwdrivers

The simplest electric screwdrivers mimic a traditional screwdriver shape. They're great for occasional use and driving screws in confined spaces. But they only offer 3.6v or 4v of power and so may struggle with tougher jobs.

A more powerful option is an impact driver. These use the same technology as impact wrenches used by garages to remove wheel nuts, only much smaller of course! Impact drivers are especially suited for large screws or for use removing rusty or damaged screws.

Generally, the higher the voltage of your electric screwdriver, the more powerful it is. A higher voltage means you'll finish the job faster before you need to recharge. (And usually a higher voltage means a heavier battery.) A screwdriver's RPM - revolutions per minute - will tell you about its motor speed. The higher the RPM, the faster your electric screwdriver will turn.

You're talking mostly cordless screwdrivers here, by the way: electric screwdrivers are usually powered by a rechargeable battery and come with a separate charger unit.

Being able to vary screwdriver speed gives you greater control. Simply adjust the pace to suit the type of screw you're using and the material you're working with. (Also see torque control below.)

Of course all electric screwdrivers come with reverse action, so you can quickly and easily remove screws if you need to.

Adjustable torque (rotating force or turning power) is a really helpful feature. Use it to control the final twisting force to match different screw sizes. Chunkier screws need more effort to turn through materials than others - that's no problem for adjustable torque. But you can also adjust to minimal power for delicate screws. Variable torque control also helps you get your screw heads flush with the surface.

The torque range you need depends on the job. An electric screwdriver with lower levels of torque is fine for light, infrequent work. You'll want a higher torque range for bigger DIY jobs with lots of screw type changes.

• Is the screwdriver handle comfortable?
• If you're left-handed check the screwdriver is comfortable to use.
• Look for a rubberised or soft-grip anti-slip handle to give you a better hold.
• How long is the life of the battery? How long does it take to recharge and does it feature a fast charge facility?
• Does the screwdriver incorporate a light? This is pretty useful when you're working in poor lighting conditions.
• Does the screwdriver come with useful extras - a carry case or a selection of screw or drill bits, for example.
• How long is the guarantee?

If you're going to do any more than just very light drilling, what about going for a drill driver? With one of these you can both drill and drive screws - this could be cheaper than buying a separate drill and electric screwdriver.