Why the tip matters
A screwdriver works by transferring turning force through its tip into the screw head. If the tip does not fit the recess well, it can slip out under load, which is often called cam-out, and the recess can become damaged. Matching the tip type and size to the screw is the single most useful thing you can do to protect your screws.
A screwdriver is used to drive and remove screws, and the tip is the part that differs between kinds.
Slotted
Slotted tips, also called flat or flathead, have a single straight blade that fits into a single groove. They are simple and widely used on older fixtures and electrical covers. They can slip sideways out of the slot, so the blade should match the slot width and thickness as closely as possible. A blade that is too narrow can damage the slot, and one that is too wide can mark the surrounding surface.
Phillips
Phillips tips have a cross shape. They are among the most common tips in household items and general construction. Phillips drivers are designed so that they can cam out when the torque gets high, which can limit over-tightening but also makes it easy to strip the recess if you do not push firmly or if the tip is the wrong size. Phillips sizes are labeled PH0, PH1, PH2 and so on, and PH2 is a very common size.
Pozidriv
Pozidriv looks similar to Phillips but has additional small marks between the arms of the cross on the screw head. The Pozidriv tip is designed to fit more fully and resist cam-out. A Phillips driver in a Pozidriv screw, or the other way around, may seem to fit but can fit loosely and wear out the recess. Look closely for the extra tick marks on the head to tell them apart. Sizes use a PZ prefix, such as PZ2.
Square (Robertson)
The square drive, often called Robertson, has a square recess and a matching square tip. It grips well and is commonly used in some regions and in decking and construction screws. Sizes are often identified by color or number in different systems, so check the packaging. In answer to which screwdriver design has a square tip, this is the one.
Torx and hex
- Torx (star) tips have a six-point star shape. They allow high torque with less slipping, and you will see them in automotive, electronics and many deck and construction screws. Sizes use a T prefix, such as T20 or T25. Tamper-resistant versions have a small pin in the center and need a matching tip with a hole.
- Hex tips fit a six-sided recess. They are used in furniture assembly and bicycles, and appear as L-shaped keys or as bits.
Other specialty tips
- JIS (Japanese Industrial Standard) cross-head screws look like Phillips but are not exactly the same. They are common on some Japanese equipment and small electronics. Using a Phillips driver can strip them, so a JIS driver is better.
- Tri-wing and spanner tips are used for tamper resistance in some devices.
- Security variants of several tip types exist. These need purpose-made drivers.
How to match a tip to a screw
- Look at the head shape. Is it a straight slot, a cross, a square, a star, or a hex?
- Check for small marks. For cross-shaped heads, look for extra marks that suggest Pozidriv, and consider the equipment’s origin for JIS.
- Test the fit. The tip should sit fully in the recess and have very little wobble.
- Choose the right size. If the tip rocks, move one size smaller or larger and test again.
- Check the packaging or documentation when the screws came with a product.
If you are unsure, a small bit set that covers the main types is often a sensible purchase, and you can test several tips quickly.
Tip sizes in brief
Different standards use different labels. Common ones include PH or PZ numbers for cross-head tips, T numbers for Torx, millimeters for hex and the width of the blade for slotted tips. The size should match the screw rather than the length of the screw. Bigger screws generally use larger drivers.
Avoiding stripped screws
- Use a tip that fits snugly.
- Press firmly into the screw as you turn, especially with cross-head tips.
- Keep the driver aligned with the screw axis.
- Replace worn tips, since rounded corners reduce grip.
- Start with lower speed if using a drill or impact driver.
A tip that is worn or damaged is more likely to slip, even if it is the right type.
Frequently asked questions
How do I know which screwdriver bit to use?
Look at the head shape, then test the tip in the recess. It should fit snugly without wobbling. If it does not, try a different size or type.
Which screwdriver design has a square tip?
The square drive, often called Robertson, uses a square tip.
What are the three main types of screw heads?
Slotted, Phillips and square are often named as three common types, though Torx and hex are also widely used.
What is the purpose of a screwdriver?
A screwdriver turns screws to fasten or loosen them. The tip must fit the head to do this well. For tools that complement screwdrivers, see our guides to pliers and hammer types.