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Spur Gear Design Calculator

Spur gear geometry and contact/bending stress per AGMA standards.

Calculate spur gear geometry and check bending stress using the Lewis equation with velocity factor.

Reference: AGMA / Lewis Equation (20° full-depth involute)

Spur Gear Design Calculator

Inputs

Results

Pitch Circle Diameter
96.00mm
Addendum Diameter
104.00mm
Dedendum Diameter
86.00mm
Circular Pitch
12.57mm
Torque
47.75N·m
Tangential Force
994.7N
Pitch Line Velocity
5.03m/s
Lewis Form Factor (Y)
0.302
Induced Bending Stress
55.1MPa
Factor of Safety
2.54

Formula Used

σ = Ft / (Cv·b·m·Y)   where Cv= 3/(3+v) [Barth's velocity factor, cut gears]
Lewis equation gives a preliminary bending-strength check only. For final design, verify surface (contact) stress per AGMA 2001-D04 and check dynamic/wear loads.

⚠ For preliminary design and educational use only. Verify all results against applicable codes and standards before use in production or safety-critical applications.

About this calculator

Part of our Mechanical Calculators collection. Beams, bolts, springs, gears, bearings, and core ME calculations.

How it works

Calculates spur gear geometry (pitch diameter, center distance, addendum, dedendum, contact ratio) and estimates bending and contact stress per AGMA 2001 simplified method.

Enter your values in the inputs above and click CALCULATE. Results appear on the right without a page reload. No login and no server upload.

Privacy and accuracy

Every calculation runs locally in your browser. Your design data never leaves your device. Results are intended for preliminary engineering work. Always verify critical designs with qualified review and applicable standards before production use.

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