Overall Diameter   mm  
  Number of Teeth   T  
  Metric Gear Size   MOD  
  Imperial Gear Size   DP  
  How to use the metric gear size estimator  
  1. Accurately measure the overall diameter of the gear  
  Note: Inaccurate measurements will lead to false results  
  2. Enter the number of teeth on the gear  
  If the gear is metric, the overall diameter measurement is accurate then the 'Metric Gear Size' result will be a Module number such as 0.25, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 1.0, 1.25, 1.5, 1.75, 2.0, 3.0, 4.0, 6.0 etc.. If the gear is imperial, then the 'Imperial Gear Size' result will be a whole DP number such as 96, 80, 72, 64, 48, 32, 24, 20, 18, 16, 14, 12, 10, 8, 6, 4. If you do not know if your gear is metric or imperial then look for the best 'fit' in the results windows.  
  Note: Gears with a small number of teeth i.e. <15 may give poor results. Some gears may give an equally good result for both metric and imperial and thus uncertain.  
  Disclaimer: Whilst we have taken evey care to ensure this calculator gives the correct answer, Gear Concern cannot be held responsible for any errors and their consequencies.