Charts
Quick reference charts for screw sizes, bolt dimensions, thread pitch, and tap drill sizes.
Universal Screw & Bolt Size Chart
The main reference page: metric vs imperial screw sizes, thread pitch vs TPI, tap drill sizes, and bolt head dimensions in one place.
View full chartBolt Grade Chart
Metric property classes and SAE grades with head markings.
Open chartScrew Size Chart
Metric to imperial screw equivalents.
Open chartTap Drill Chart
Metric tap drill sizes for common threads.
Open chartVisual identification
Thread and diameter tables above are separate from head shape and drive recognition—use the visual reference when you need to match what you see.
Screw heads & drives