Protein Needs Calculator
Get a simple, evidence-informed daily protein target based on your body weight, age, and activity level.
This tool offers general education only and does not replace individualized medical or nutrition advice. If you live with kidney disease or another condition that affects protein handling, please speak with your physician or dietitian before changing your protein intake.
Why this number?
Most general guidelines use 0.8 grams of protein per kilogram of body weight a day as a baseline. That figure was set to prevent deficiency, not to support optimal muscle health, and current research suggests it is too low for most adults, particularly as we age.
This calculator instead starts at 1.0 to 1.2 grams per kilogram as a baseline, and adjusts upward for two reasons. First, age: after 50, and especially after 65, the body becomes less efficient at using dietary protein to build and maintain muscle, a change researchers call anabolic resistance. Second, physical activity: resistance training and higher levels of physical activity increase the amount of protein the body can use to repair and build muscle tissue.
The result is given as a range rather than a single number, since individual needs vary and a range better reflects what the research actually supports.
A note on how this calculator works
Some protein recommendations in the research literature are expressed in grams per kilogram of lean body mass rather than total body weight. Lean body mass is typically measured through specialized methods such as DEXA scanning or bioelectrical impedance analysis, and most people do not have ready access to this information. To keep this tool practical and simple to use, the calculator above works from total body weight instead, consistent with how the majority of the clinical literature cited below expresses its recommendations.
References
- Traylor, Daniel A., Stefan HM Gorissen, and Stuart M. Phillips. "Perspective: protein requirements and optimal intakes in aging: are we ready to recommend more than the recommended daily allowance?" Advances in Nutrition 9.3 (2018): 171-182.
- Bauer, Jürgen, et al. "Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group." Journal of the American Medical Directors Association 14.8 (2013): 542-559.
- Phillips, Stuart M., Stéphanie Chevalier, and Heather J. Leidy. "Protein "requirements" beyond the RDA: implications for optimizing health." Applied Physiology, Nutrition, and Metabolism 41.5 (2016): 565-572.
- Wu, Wenxuan, et al. "Dietary protein requirements of older adults with sarcopenia determined by the indicator amino acid oxidation technology." Frontiers in Nutrition 12 (2025): 1486482.
- Jäger, Ralf, et al. "International society of sports nutrition position stand: protein and exercise." Journal of the International Society of Sports Nutrition 14.1 (2017): 20.
