Screw Thread Calculator
Calculate thread dimensions, stress, and torque specifications for metric and imperial threads
About this calculator
The Screw Thread Calculator is an essential engineering tool that accurately computes thread dimensions, stress analysis, and torque specifications for both metric and imperial screw threads. This calculator helps engineers, machinists, and designers determine critical parameters like pitch diameter, thread depth, root diameter, and maximum allowable stress to ensure proper fastener selection and joint integrity. Whether you're designing mechanical assemblies, performing failure analysis, or specifying hardware requirements, this tool provides precise calculations that comply with international threading standards and safety factors.
How to use
Select your thread system (metric or imperial) and input the basic thread designation or nominal diameter. Enter additional parameters like thread pitch, length of engagement, and material properties as required. The calculator will automatically compute all relevant thread dimensions, stress concentrations, and recommended torque values based on standard formulas and safety factors.
Frequently asked questions
What's the difference between major and minor thread diameter?
Major diameter is the largest diameter of the thread (outer edge), while minor diameter is the smallest diameter at the root of the thread.
How do I calculate thread engagement length?
Thread engagement length is typically 1-1.5 times the bolt diameter for steel connections, or 2-3 times for softer materials like aluminum.
What safety factor should I use for thread stress calculations?
Use a safety factor of 2-4 for static loads and 4-8 for dynamic or fatigue loading conditions, depending on application criticality.