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Inch to millimetre thread calculator

Inch to millimetre thread calculator

Convert inch nominal diameter and TPI to millimetres and metric pitch, then compare nearby metric sizes without claiming compatibility. Inputs, formula and interpretation are separated so you can verify the result before using it for a configurable part.

Calculate

Convert inch nominal diameter and TPI to millimetres and metric pitch, then compare nearby metric sizes without claiming compatibility
Inputs: Inches
Inputs: TPI

Schematic illustration – not to scale.

Inch to millimetre thread calculatorSchematic illustration – not to scale. Inches, TPI mm = inch × 25.4TPI / p

Schematic illustration – not to scale.

Formula

mm = inch × 25.4

Thread values are calculation aids. Metric and Unified threads are not automatically compatible.

Step by step

  1. Enter the measured or planned values with their units.
  2. Check the formula with substituted values in the result area.
  3. Copy the parameters or open a related product for configuration.

Complete worked example

Worked example with typical workshop values: insert the inputs, apply mm = inch × 25.4 and compare the result with the reference table.

23060 mm
14040 mm
32060 mm

Assumptions and limitations

  • Thread values are calculation aids. Metric and Unified threads are not automatically compatible.

Common input mistakes

  • Decimal comma and point are accepted, but do not type units into numeric fields.
  • For gears, the tooth count must be a whole number in practice.

FAQ

Are metric and UNC/UNF threads interchangeable?

No. Similar diameters do not mean profile, pitch and tolerance are compatible.

Can I manufacture directly from this result?

Use the value as a calculation and configuration aid. Loaded or standards-critical parts need engineering review.

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