Screwdriver Types and Sizes: Phillips, Slotted and Torx

Match the screwdriver tip to the screw head type and size. A Phillips PH2 tip fits most general screws, PH1 fits small ones and PH3 large ones; a slotted tip must fill the slot width; Torx T20 and T25 fit many deck and construction screws. A tip that fits snugly and is pushed in firmly strips fewer heads than one that is slightly loose.

Screwdriver tip types at a glance

Tip	Looks like	Common sizes	Common use
Phillips (PH)	Cross with a tapered point	PH0, PH1, PH2, PH3	General screws, drywall and wood screws
Pozidriv (PZ)	Cross with extra ribs	PZ1, PZ2, PZ3	European furniture, cabinets, construction screws
Slotted	One flat blade	Width 1/8 to 3/8 in (3 to 10 mm)	Old hardware, electrical terminals
Torx (star)	Six-point star	T10, T15, T20, T25, T30	Decks, construction screws, car and electronics
Square (Robertson)	Square socket	#1, #2, #3	Decking and framing screws, common in Canada
Hex	Hexagon	1.5 to 10 mm, 1/16 to 3/8 in	Furniture and machine screws; see the Allen wrench size chart

Phillips sizes

PH0 and PH1 are for small screws (electronics, hinges and other small hardware), PH2 is the all-round size for most household and construction screws, and PH3 is for large screws. If the tip wobbles in the head, it is probably too small; go up a size.

Phillips vs Pozidriv

The two look alike, but a Pozidriv screw has small ribs between the arms of the cross, and its driver has a blunt tip. Using a Phillips driver in a Pozidriv screw makes the tip slip out under load. Check for the ribs before you pick the bit.

Slotted screwdrivers

A slotted tip should fill the slot from end to end, and be as thick as the slot. A tip that is too narrow chews the edges, and one that is too wide marks the surrounding surface. Slotted screwdrivers are often used for light prying, but the blade bends and chips if you do that regularly.

Torx and square drive

Torx and square (Robertson) sockets grip the tip firmly and slip far less than a Phillips cross. That is why deck and construction screws often use them. Fit the tip all the way into the socket before turning; a half-seated tip rounds out the socket.

How to avoid stripping a screw

1. Choose the right type and size for the head.
2. Push firmly down while you turn, particularly with Phillips heads.
3. Keep the driver in line with the screw.
4. Drill a pilot hole in hardwood so the screw does not bind; see the pilot hole calculator.
5. In a drill or driver, set the clutch low enough that it clicks before the head strips; drill clutch settings explains the numbers.
6. Replace worn tips. A rounded tip slips even on a good screw.

For a screw that has already stripped, a wider rubber band between the tip and the head can add grip. Failing that, a screw extractor removes the screw. For tightening to a set value, use a torque wrench or a torque screwdriver.