Daily Protein Needs Calculator

Estimates daily protein intake based on body weight, activity level, and goal (general health, fat loss, muscle gain, athletic performance). Reference ranges are 0.8 g/kg for sedentary adults, 1.2–1.6 g/kg for active individuals, 1.6–2.2 g/kg for resistance-training and hypertrophy goals.

Output is given in grams per day with a recommended distribution across three to five meals. Per-meal targets help ensure muscle protein synthesis is stimulated repeatedly, since a single bolus saturates the response.

The recommended ranges derive from nitrogen-balance studies, indicator amino acid oxidation methods, and direct hypertrophy outcomes. The 0.8 g/kg US RDA is a minimum to prevent deficiency in 97.5% of healthy adults, established through nitrogen balance in the 1970s. Modern research using more sensitive methods (IAAO) suggests 1.2 g/kg is closer to the actual minimum for sedentary adults, with active individuals needing more. The American College of Sports Medicine, ISSN, and most contemporary sports nutrition bodies recommend 1.4–2.2 g/kg for athletes.

The 1.6 g/kg figure for resistance-training adults comes from a 2018 meta-analysis (Morton et al., British Journal of Sports Medicine) which found additional protein beyond this point produced no further hypertrophy benefit in trained subjects. The "leucine threshold" hypothesis suggests muscle protein synthesis requires roughly 2.5–3 g of leucine per meal, achieved through 25–40 g of high-quality protein. Distributing intake across 3–5 meals stimulates synthesis more frequently than two large meals and produces measurably better outcomes in trained populations.

A worked example for an 80 kg adult resistance training four times per week with body recomposition goals: target 1.8 g/kg = 144 g/day. Distributed across four meals: 36 g per meal. Practical translation: chicken breast (35 g protein per 150g cooked), Greek yogurt cup (15–20 g), whey protein scoop (24 g), eggs (6 g each). A typical day might be eggs + Greek yogurt at breakfast (~30 g), chicken and rice at lunch (40 g), whey shake post-workout (24 g), salmon and vegetables at dinner (35 g), cottage cheese before bed (25 g). Total ~154 g, on target with margin.

Excess protein is largely safe for healthy individuals. Studies up to 3.0 g/kg over 12+ months show no measurable kidney harm in subjects with normal renal function. The "high protein damages kidneys" claim originated in research on patients with pre-existing kidney disease, where protein restriction is sometimes therapeutic. Adequate hydration accompanies higher intakes; the body excretes urea efficiently when fluid is sufficient.

Limitations: the calculator uses total body weight, which overshoots for individuals at high body fat percentages. A 120 kg adult at 35% body fat has roughly 78 kg of lean mass; protein needs scale closer to lean mass than total weight at extremes. The simple total-weight version is adequate for most active individuals between 15–25% body fat. For obesity-class subjects in deficit, lean-mass-based targeting reduces estimated needs by 15–25%.