💪 Bicep Size Potential
Estimate your genetic arm size potential using the classic Steve Reeves formula.
Measure around the narrowest part of your wrist.
Your Ideal Arm Size
Ideal Size Goal
Wrist × 2.5
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Genetic Ceiling Maximum
Wrist × 2.8
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Where the Steve Reeves formula comes from
Steve Reeves was a 1950s bodybuilder famous for classic, balanced proportions rather than raw size. His approach tied each measurement back to wrist and ankle circumference — markers of skeletal frame that don't change with training. The idea: a larger frame can carry more muscle, so your wrist gives a rough ceiling for what arm size will look proportional and be naturally attainable.
This calculator applies the commonly cited multipliers: an ideal flexed arm around 2.5× your wrist, and a practical natural ceiling near 2.8×. Treat these as directional targets, not guarantees. Real arm size depends on overall body mass, training volume, nutrition, and body-fat level. If you're chasing size, the TDEE & macro calculator will help you set the calorie surplus that actually drives growth.