Protein Intake Calculator
Estimate daily protein need (grams) from body weight, training intensity, and goal (maintain, build, or lose weight). Targets evidence-based ranges for active people: 1.2–2.2 g protein per kg body weight depending on activity and objective.
Last updated: May 2026
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About this calculator
Protein needs scale with body mass, training stress, age, and goal. This calculator combines all three into one number: protein_g = weight_kg × activity_level × goal_multiplier, where activity_level ranges from 0.8 (sedentary, WHO baseline) to 2.2 (intense training), and goal_multiplier is 0.9 (lose weight), 1.0 (maintain), or 1.2 (build muscle). The result is a per-day protein target in grams. Variables: weight in kg, activity_level and goal as multipliers. Why protein matters: it provides the amino acid substrate for muscle protein synthesis (MPS), supports immune function and enzyme/hormone production, has the highest thermic effect of any macronutrient (~25–30% of its calories are spent on digestion, versus ~5–10% for carbs and ~0–3% for fat), and is the most satiating macro per calorie. Evidence-based per-kg targets to remember: 0.8 g/kg = WHO baseline for sedentary healthy adults (deficiency floor, not optimum); 1.2–1.4 g/kg = recreational exerciser; 1.6–2.0 g/kg = strength athlete or person in a calorie deficit trying to preserve muscle; 2.0–2.5 g/kg = elite physique athlete or extreme cuts; above 2.5 g/kg = diminishing returns for most goals. Spreading protein across 3–5 meals of 0.3–0.4 g/kg each maximises MPS better than the same total in 1–2 meals. Edge cases: kidney disease patients need lower targets (0.6–0.8 g/kg) prescribed by a nephrologist; pregnancy and lactation add 10–25 g/day on top of baseline; very obese individuals should use lean body mass or a target weight (not total weight) to avoid overshooting. Quality matters: complete proteins (animal, soy, quinoa) provide all essential amino acids; combining plant sources across the day works equally well.
How to use
Example 1 — Recreational lifter aiming to maintain. You weigh 75 kg, train moderately (1.6), and want to maintain (1.0). Enter Weight = 75, Activity = Moderate (1.6), Goal = Maintain (1.0). Result = 75 × 1.6 × 1.0 = 120 g/day. ✓ That's 1.6 g/kg — right in the recommended range for someone strength training, with enough protein to support recovery and lean mass. Example 2 — Building muscle, intense training. You weigh 80 kg, train intensely (2.2), and want to build muscle (1.2). Enter Weight = 80, Activity = Intense (2.2), Goal = Build Muscle (1.2). Result = 80 × 2.2 × 1.2 = 211.2 ≈ 212 g/day. ✓ That's ~2.65 g/kg — above the typical 1.6–2.2 g/kg range and at the high end of what most evidence supports. For most lifters, 1.6–2.2 g/kg is sufficient for muscle gain; this calculator's multiplier compounding can produce numbers above the practical optimum. Treat very high outputs as an upper bound rather than a target.
Frequently asked questions
How much protein do I actually need?
Depends on what you're trying to do. WHO baseline for sedentary healthy adults is 0.8 g/kg/day — enough to prevent deficiency. For general health with regular exercise, 1.2–1.4 g/kg is reasonable. For building muscle with progressive strength training, 1.6–2.0 g/kg consistently produces best results in randomised trials. For preserving muscle in a calorie deficit (cutting), 1.8–2.2 g/kg minimises muscle loss. Above 2.2 g/kg there's diminishing benefit for most people, though physique athletes sometimes push to 2.5–3.0 g/kg during extreme cuts. Older adults (60+) benefit from the higher end (1.2–1.5 g/kg) even when relatively sedentary, to combat age-related muscle loss (sarcopenia). Personalise based on goal, training, and individual response.
Does protein timing matter for muscle gain?
Distribution matters more than precise timing. Muscle protein synthesis (MPS) is maximally stimulated by ~0.3–0.4 g/kg of high-quality protein per meal, with diminishing returns above that. Spreading total daily protein across 3–5 meals each containing this amount produces more MPS over 24 hours than the same total in 1–2 large meals (the "muscle full" effect — too much in one meal saturates MPS, with the excess oxidised for energy). The "anabolic window" (you must eat protein within 30 minutes after a workout) is largely overblown; the muscle is sensitive to protein for several hours post-workout, so any meal within ~2 hours captures the bulk of the benefit. Pre-sleep casein (40 g) has modest additional benefit for muscle preservation overnight. Total daily intake is by far the most important variable; if you're hitting your daily total in 3–4 meals, you're fine.
Is high protein bad for kidneys or bones?
For healthy people with normal kidney function, no — well-controlled studies consistently show high-protein diets (up to 3 g/kg/day) don't damage kidneys. The "high protein hurts kidneys" myth comes from extrapolation: people with existing chronic kidney disease do benefit from protein restriction to slow progression, and this got generalised incorrectly to healthy populations. The acid-load hypothesis (that high protein leaches calcium from bones) is also unsupported by recent research; the higher calcium loss is largely offset by improved calcium absorption, and high-protein diets are actually associated with better bone density in older adults. Adequate hydration matters at high intakes (more nitrogen waste to clear), but for kidney-healthy people the practical ceiling is appetite, budget, and crowding out of other essential nutrients (fibre, fats, micronutrients), not safety.
What are the most common mistakes people make with protein targets?
The first is using the WHO 0.8 g/kg minimum as a target while training — that's the floor to prevent deficiency, not the optimum for active people. The second is concentrating intake in 1–2 large meals rather than spreading across the day. The third is over-relying on protein powders while neglecting whole-food sources, which provide additional micronutrients, fibre (plants), and satiety. The fourth is using "goal weight" instead of actual body weight for the calculation, underestimating need. The fifth is mixing units — g/kg vs g/lb differ by ~2.2× and a slip produces dramatically wrong targets. The sixth is over-thinking specific protein quality (animal vs plant, complete vs incomplete) — total daily intake from any reasonable food source dominates, and protein blends in mixed meals provide more than enough essential amino acids. Finally, people often forget that very high intakes can crowd out carbohydrates needed for hard training; 4–7 g/kg/day of carbs alongside adequate protein is the right balance for serious athletes.
When should I not use this calculator?
Skip it if you have chronic kidney disease, diabetic nephropathy, or any diagnosed kidney impairment — protein recommendations for those conditions come from your nephrologist, typically much lower than this calculator suggests. Don't use it during pregnancy or lactation, which require additional protein (+10–25 g in pregnancy, +20 g during breastfeeding) on top of normal needs. Avoid it for elite athletes in specific events (ultra-endurance, bodybuilding cuts, weight-cutting combat sports) where individualised macro programming based on phase of training matters more than a generic formula. It's also unreliable for very obese individuals (BMI > 40) — using total body weight overstates lean mass and protein need; use lean body mass or a target weight. Finally, don't use it as your only nutrition planning tool — total calories, carb-fat balance, fibre, and micronutrient adequacy matter as much as protein. For active intense-training-plus-building goals the calculator's multiplier compounding can produce very high numbers; treat the high end as a ceiling, not a daily quota.