Threading Calculator — Basic · Manual

Threading Calculator — Enhanced (Presets & Material Guidance)

Choose a preset or enter values manually. Material selection gives recommended tap type and a recommended thread % range (min/max) based on common practice and material properties.

Thread system

Tap type

Preset quick select (optional)

Nominal diameter (D)

enter as mm (metric) or inches (imperial)

Pitch P (mm) or TPI (imperial)

e.g., 1.0 (mm) or 20 (TPI)

Number of thread starts

Lead = pitch × starts

Target % thread (Hp)

Default 75% (manual tapping). Material recommendations shown below.

Tap starts (manual taps usually 1)

Material (select for guidance)

Material guidance appears here.

Notes / shop conditions

Summary

—

Nominal diameter (D)

—

Pitch (P)

—

TPI (if imperial)

—

Lead (advance/rev)

—

Tap drill (cut tap)

—

Tap drill (form tap)

—

Thread % target

—

Recommended Hp range

—

Tap type suggested

—

Suggested nearest drill

—

Notes

—

Formulas: Cutting tap (metric): TD = D − (Hp × P) / 76.98. Forming tap uses divisor 294.12. Imperial uses TPI conversions. Default Hp = 75% for manual tapping unless material guidance suggests otherwise.