Thread Calculator
Calculate metric and imperial thread dimensions, tolerances, and specifications
Calculate Thread Dimensions
The nominal diameter of the thread (e.g., 6 for M6 thread)
Distance between thread crests in millimeters
Thread Dimensions
⚠️ Engineering Safety Warning
• This calculator provides basic thread dimensions for reference purposes
• Always verify calculations against current standards (ISO 68, ANSI B1.1, etc.)
• Consider material properties, load requirements, and environmental conditions
• Improper thread specifications can lead to fastener failure and safety hazards
• Consult engineering specifications and quality standards for critical applications
• Thread tolerances must match application requirements and manufacturing capabilities
Example Calculation: M6 × 1.0 Metric Thread
Thread Specifications
Callout: M6 × 1.0 (6mm diameter, 1.0mm pitch)
Application: Standard coarse thread for 6mm fasteners
Standards: ISO 68-1, ISO 965-1
Common uses: General fastening, machine screws, bolts
Dimension Calculation
• Major Diameter (d) = 6.000mm (nominal)
• Fundamental Triangle Height (H) = 1.0 × √3/2 = 0.866mm
• Pitch Diameter (d₂) = 6.000 - (3/4) × 0.866 = 5.350mm
• Minor Diameter (d₁) = 6.000 - (5/4) × 0.866 = 4.917mm
• Thread Depth = (5/8) × 0.866 = 0.541mm
Result: Standard M6 × 1.0 thread dimensions
Standard Metric Threads
Coarse Pitch (mm)
Thread Applications
Fasteners
Bolts, screws, nuts, and threaded rods
Pipe Connections
NPT, BSP, and metric pipe threads
Machine Parts
Lead screws, adjustment mechanisms
Precision Equipment
Micrometers, measurement devices
Key Formulas
Understanding Thread Calculations
What are Threads?
Threads are helical grooves and ridges wrapped around a cylindrical shaft that convert rotational motion to linear motion. They provide mechanical advantage and create strong, removable connections between parts. Thread geometry is precisely defined by international standards to ensure compatibility.
Basic Thread Dimensions
- •Major Diameter: Largest diameter (nominal size)
- •Pitch Diameter: Effective diameter for thread engagement
- •Minor Diameter: Smallest diameter (root of threads)
- •Thread Pitch: Distance between corresponding points
Thread Calculation Formulas
H = P × √3/2
d₂ = d - (3/4) × H
d₁ = d - (5/4) × H
- H: Fundamental triangle height
- P: Thread pitch
- d: Major diameter
- d₂: Pitch diameter
- d₁: Minor diameter
Thread Standards
Metric (ISO 68)
60° thread angle, M designation (M6 × 1.0)
Imperial (ANSI B1.1)
60° thread angle, UNC/UNF designation
Pipe Threads
NPT (tapered), NPTF, BSP standards