Interactive Screw Identifier
Identify screw and bolt types by head shape, drive recess, and thread system. Built like a diagnostic—not a quiz. Select what you see, then jump to measurement tools to confirm.
What is a screw identifier? A screw identifier helps determine the likely type of fastener based on its head shape, drive type, and thread system (metric, imperial, or unknown). It narrows candidates before you measure thread diameter and pitch for a definitive match.
Head type
What does the head look like from the side or top?
Drive type
What pattern does your bit engage?
Thread system
Optional—narrows example callouts. Choose Unknown if you have not measured yet.
Results
Not sure? Measure your screw to confirm diameter and pitch.
Open Thread IdentifierCommon questions
How do I identify a screw?
Start with what you can see—head profile and drive recess—using this tool. Then measure major diameter and pitch (or TPI) and enter them in the Thread Identifier.
What is the difference between Phillips and Pozidriv?
Pozidriv has extra shallow radial ticks between the main blades and needs a Pozidriv bit; it usually grips better than Phillips when matched. See drive types reference.
Can I identify thread size visually?
No—thread diameter and pitch are not visible reliably. Visual ID narrows the family; measurement confirms the standard.
What is a screw identifier?
A structured way to narrow fastener type from head, drive, and thread system before you use calipers and gauges.