The WeighTrainer

Maximum Drug-Free Bodybuilding Potential Calculator

by Casey Butt

The following calculator gives you an estimate of the maximum muscular measurements (at roughly 8 to 10% bodyfat) that a drug-free genetically superior trainee of your structure is likely to attain. It is based on equations I've developed through over 6 years of research and analysis of data from drug-free champions both past and present. In essence, this calculator scales the measurements of history's largest drug-free bodybuilding champions to your skeletal structure. Also included are the largest trustworthy measurements I am aware of for some of drug-free bodybuilding's greatest champions, along with the calculator's predictions of their absolute potential. The article presenting the equations utilized by this calculator can be found here: Maximum Drug-Free Bodybuilding Potential



  • Height - your height without shoes.
  • Wrist - the circumference around your wrist just below the styloid process, on the hand side. (The styloid process is the bony lump on the outside of your wrist.) The hand should be open.
  • Ankle - the circumference of your ankle at the smallest point between the calf muscle and the ankle.
Height inches
Wrist inches
Ankle inches



Bodybuilder Chest Biceps Forearms Neck Quads Calves
Reg Park 52.0 / 52.0 19.0 / 19.2 NA / 15.2 19.0 / 19.0 28.0 / 28.0 18.0 / 18.4
John Grimek 50.0 / 51.3 18.5 / 18.5 14.5 / 14.6 17.8 / 18.3 27.0 / 28.3 17.7 / 18.3
Steve Reeves 49.5 / 50.9 18.3 / 18.6 14.5 / 14.7 18.3 / 18.4 26.0 / 27.7 18.3 / 18.3
Current World Champ. "B" NA / 46.5 16.7 / 17.1 NA / 13.5 15.5 / 16.9 23.0 / 25.2 16.0 / 16.4
Current Nat. 1st Place "A" 47.3 / 50.2 17.5 / 18.3 NA / 14.5 17.8 / 18.1 25.5 / 27.4 16.5 / 17.8
Current Nat. 1st Place "B" NA / 47.7 17.2 / 17.4 NA / 13.7 17.0 / 17.1 24.5 / 26.1 15.5 / 17.0
* actual measurement / predicted measurement



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