CalcVitalsProtein Calculator — How Much Per Day?
Protein needs scale with body weight and goal. The official baseline is 0.8 g per kilogram, but for building muscle the evidence points to about 1.6 g/kg — 112 g a day at 70 kg — and up to 2.2 g/kg when dieting hard to protect muscle.
How it works
The 0.8 g/kg figure on food labels is a minimum to avoid deficiency in sedentary people — the protein equivalent of a starvation floor, not an optimum for anyone who trains or diets. Meta-analyses of resistance-training studies find muscle gain tops out around 1.6 g/kg a day, with the benefit largely arriving by 1.2–1.4. In a calorie deficit the logic flips upward: higher protein (2.0–2.2 g/kg, and higher still per kilogram of lean mass) measurably spares muscle while fat is lost.
Distribution matters less than the total, but it is not nothing: muscle protein synthesis responds per meal, and four feedings of roughly a quarter of the day's protein each — typically 25–45 g of quality protein — is a sensible, evidence-friendly pattern. The leucine-rich sources (dairy, eggs, meat, soy) trigger the response most efficiently.
The fear that high protein harms healthy kidneys has not survived testing in healthy adults at these intakes over study durations. People with existing kidney disease are a different case and follow their clinician's figure, not a calculator's.
The method
Daily protein = body weight (kg) × goal factor: 0.8 (RDA baseline), 1.2 active, 1.6 muscle gain (per Morton et al., British Journal of Sports Medicine meta-analysis), 2.0–2.2 dieting (per ISSN position stand ranges).
Frequently asked questions
How much protein is too much?
For healthy adults, intakes up to about 2.2–2.5 g/kg have shown no harm in trials, just diminishing returns. Beyond the point your muscles can use, extra protein is simply expensive energy.
Can I build muscle at 0.8 g/kg?
Some, especially as a beginner — but the research consensus is that gains are measurably smaller than at 1.6 g/kg. The RDA was designed to prevent deficiency, not to optimise training.
What if I am vegetarian or vegan?
The same totals apply; just build meals from complementary sources (grains plus legumes, soy foods, dairy and eggs if you eat them) and lean toward the top of the range, since plant proteins are slightly less complete on average.