FullCalculator

Thread Pitch Calculator

Pitch to TPI Converter

Convert metric pitch (mm) to threads per inch

TPI to Pitch Converter

Convert threads per inch to metric pitch (mm)

Common Thread Reference

Look up standard metric and imperial thread sizes

Formula

TPI = 25.4 / Pitch (mm) | Pitch (mm) = 25.4 / TPI

Frequently Asked Questions

How do I convert thread pitch to TPI?
Divide 25.4 by the pitch in millimeters. For example, a 1.5mm pitch = 25.4 / 1.5 = 16.93 TPI. Conversely, divide 25.4 by TPI to get pitch in mm.
What is the difference between UNC and UNF threads?
UNC (Unified National Coarse) has fewer threads per inch and is the most common standard. UNF (Unified National Fine) has more threads per inch, providing greater tensile strength and finer adjustment but is more prone to cross-threading.

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