Thread Calculator
Calculate thread pitch, lead, approximate pitch diameter, minor diameter, and tap drill size for common metric and unified 60° screw threads.
Enter thread details
Result
Enter the nominal diameter and pitch to calculate thread dimensions.
Pitch vs. TPI
Metric threads use the distance between adjacent crests in millimetres. Unified threads commonly use threads per inch.
Lead and thread starts
Lead is the axial travel in one revolution. For a single-start thread, lead equals pitch; multi-start threads travel farther.
Tap drill guidance
A common approximation subtracts pitch from nominal diameter, then adjusts for the selected percentage of thread engagement.
Frequently asked questions
What does nominal diameter mean?
It is the named outside diameter of the thread, such as 10 mm for an M10 thread or 0.5 inch for a 1/2-inch thread.
What is thread pitch?
Pitch is the distance from one thread crest to the next. For inch threads, pitch equals 1 divided by TPI.
What is a multi-start thread?
A multi-start thread has two or more intertwined thread helices. Its lead equals pitch multiplied by the number of starts.
Are these dimensions exact manufacturing limits?
No. They are useful estimates. Production work should use the appropriate standard tolerance class and inspection method.
Results are estimates generated locally in your browser from standard geometry, material yield and waste assumptions. They are for planning purposes only, not engineering, structural, code or supplier advice. Confirm dimensions, material strength, delivery constraints and local building codes with a licensed professional before purchasing or building. VisionVix accepts no liability for decisions based on this tool's output.
