Get the full set of gear dimensions from module (or diametral pitch), tooth count and pressure angle: pitch diameter, outside diameter, root diameter and base diameter.
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Request a Proposal →Spur gear dimensions are determined by the module (metric) or diametral pitch (imperial) and the number of teeth. This calculator uses standard involute gear geometry for 20 deg pressure angle -- the most common in industrial gearing.
Module (m) is metric: m = pitch diameter / number of teeth (mm). DP is imperial: DP = number of teeth / pitch diameter (inches). Conversion: module = 25.4 / DP. A DP 8 gear ≈ module 3.175. Metric gears are specified by module; imperial by DP.
20 deg is the modern standard (ISO 53, AGMA 201.02). Older machinery sometimes uses 14.5 deg (older AGMA standard). 25 deg is used for high-strength gears. The pressure angle affects tooth thickness, contact ratio, and the minimum number of teeth before undercutting.
Yes, with an involute gear cutter (form-milling) or by generating the profile via CNC hobbing cycles. Form-milling uses a cutter shaped like the tooth space. For one-off gears, 3+2 axis milling with a ball end mill can approximate the involute profile.
Enter the module and number of teeth. The calculator gives all major spur gear dimensions per ISO 53 (20 deg pressure angle). Use these values for gear blank turning, gear cutting setup, and over-pin inspection measurements.
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