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Body fat percentage calculator

A tape measure and three numbers. The US Navy method estimates your body fat to within a few percent and shows how much of your weight is lean mass: the part we want to keep.

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The other tools
1Maximum muscle mass potential 2Body fat percentage calculator 3Maintenance calories calculator 4Body recomposition macros calculator 5Daily food tracking simulator 6Vitamin D and sunlight calculator 7Food preferences for your meal plan 8Reverse dieting and maintenance roadmap
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These tools give general estimates for healthy adults and are not medical advice. If you are pregnant, breastfeeding, under 18, or have a medical condition or a history of disordered eating, talk to your doctor before changing how you eat.

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Protein requirements by age and goal

Protein does far more than build muscle. It is a vital part of the work done inside every cell, and of the structure and function of your tissues and organs. The more active you are, especially with resistance training, the higher your needs.

Where you fall in the range depends on two things:

  1. Calorie deficit or surplus. In a deficit you need more, to protect your lean mass.
  2. Your age. Protein needs rise as we get older, because of age-related muscle loss (sarcopenia).
Grams of protein per kg of lean body mass a day
AgeCalorie surplus
gain muscle		Calorie deficit
lose fat
0–30 years1.8–2.02.2–2.4
31–40 years2.0–2.32.4–2.8
41–50 years2.3–2.62.8–3.1
51–60 years2.6–2.93.1–3.5
61–70 years2.9–3.23.5–3.8

If you strength-train, aim for the higher end of your range. Needs are highest in older adults and in anyone in a calorie deficit, to protect lean mass, which matters for performance, looks and metabolic health.

How our calculators use this. Protein is set per kg of lean mass, from your body fat % or, if you leave it empty, an estimate from your height and weight. At maintenance and in a surplus we use the surplus column; for fat loss and recomposition, the deficit column. More strength sessions, and a bigger deficit, move you towards the top of your range.

From Alexandra Lasconi’s protein guide.

References
  1. Dietary protein and exercise have additive effects on body composition during weight loss in adult women
  2. Dietary Guidelines should reflect new understandings about adult protein needs
  3. A high protein diet (3.4 g/kg/d) combined with a heavy resistance training program improves body composition in healthy trained men and women
  4. The effects of consuming a high protein diet (4.4 g/kg/d) on body composition in resistance-trained individuals
  5. A systematic review of dietary protein during caloric restriction in resistance trained lean athletes
  6. A high proportion of leucine is required for optimal stimulation of the rate of muscle protein synthesis by essential amino acids in the elderly
  7. Leucine or carbohydrate supplementation reduces AMPK and eEF2 phosphorylation and extends postprandial muscle protein synthesis in rats
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