Use this engineering calculation for a transparent preliminary estimate or independent arithmetic check when geometry, materials, loads, operating conditions, and units are defined consistently.

Pitch Diameter Millimeters (mm)

Required number input.

Tooth Count

Required integer input.

Metric spur-gear module m=d/z from pitch-circle diameter in millimeters and whole tooth count. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Module Millimeters (mm)

The resulting module millimeters returned as a number.

• Gear ratios describe ideal kinematics. Tooth counts, module, pressure angle, center distance, backlash, undercut, strength, efficiency, lubrication, alignment, dynamics, and service factor determine a workable transmission.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check assumptions against drawings, measurements, current material data, and the applicable design code. Apply required load combinations and safety factors, then obtain qualified review and testing for consequential designs.

• Worm Gear Ratio

  Ideal worm gear reduction ratio from wheel tooth count divided by worm starts.

• Bevel Gear Pitch Angle

  Pitch cone angle of the first straight bevel gear in a 90° intersecting-shaft pair: atan(z1/z2).

• Cutting Speed

  Cutting surface speed in meters per minute from rotating tool or workpiece diameter in millimeters and spindle RPM.