Protein Calculator

Estimate your optimal daily protein intake based on body weight, activity level, and specific goals — backed by RDA, ISSN, and WHO guidelines.

Quick examples:
70kg, sedentary
80kg, muscle gain
65kg, fat loss
75kg, older adult
68kg, marathon training
100% private — all calculations run locally in your browser. No data stored or shared.

Why protein matters: science & physiology

Protein is a fundamental macronutrient responsible for muscle repair, enzyme production, immune function, hormone synthesis, and satiety. The Recommended Dietary Allowance (RDA) for healthy adults is 0.8 g per kilogram of body weight — this prevents deficiency but may not be optimal for active individuals, aging populations, or those aiming for body composition changes. Leading organizations including the International Society of Sports Nutrition (ISSN) and American College of Sports Medicine (ACSM) recommend higher intakes (1.6–2.2 g/kg) for athletes and people engaged in resistance training. For older adults, protein becomes even more critical to counteract sarcopenia (age‑related muscle loss), with recommended levels of 1.0–1.2 g/kg or higher.

Recent meta‑analysis: A 2018 systematic review (Morton et al., PMID: 28698222) found that protein supplementation beyond 1.6 g/kg/day provided no further gains in fat‑free mass in resistance‑trained individuals. Our calculator respects this upper boundary. Additionally, a 2020 meta‑analysis (Hector et al., PMID: 32845215) confirms higher protein (≥1.6 g/kg) during caloric restriction preserves lean mass.

? General formula: Daily protein (g) = body weight (kg) × protein coefficient (g/kg)
Coefficients vary by goal, age, and diet type (plant‑based +15% adjustment).

How the calculator works

Our tool uses evidence‑based coefficients derived from systematic reviews and meta‑analyses (e.g., Morton et al., 2018; Schoenfeld & Aragon, 2018). You select your primary goal, and we compute a minimum–maximum range along with an optimal midpoint. For weight loss/fat loss, higher protein preserves lean mass and increases thermogenesis. For muscle gain, we apply the ISSN‑endorsed range of 1.6–2.2 g/kg. For older adults, we incorporate the PROT‑AGE study recommendations. Optionally the "age >65" toggle adds a conservative 10% boost. The tool also converts pounds to kilograms automatically (1 lb = 0.4536 kg). A plant‑based diet checkbox adds a 15% increase to compensate for lower digestibility (upper limit 2.2 g/kg).

Step‑by‑step use

  1. Enter your current body weight (kilograms or pounds).
  2. Choose your goal or activity level from the dropdown (sedentary, muscle gain, fat loss, endurance, older adult).
  3. If you are 65+ years old, you may check the optional boost for age‑related needs.
  4. If you follow a plant‑based diet, check the corresponding box for a +15% adjustment.
  5. Click “Calculate my protein” — you’ll see a recommended daily range, grams per kilogram, per‑meal guidance, and an interactive bar chart.

Reference ranges & examples

Goal / Profile Protein coefficient (g/kg/day) Example (70 kg person)
Sedentary / General health 0.8 56 g/day
Active lifestyle / Recreation 1.2–1.5 84–105 g/day
Muscle gain (strength training) 1.6–2.2 112–154 g/day
Fat loss / Calorie deficit 1.6–2.0 112–140 g/day
Endurance athlete 1.2–1.6 84–112 g/day
Older adult (65+) 1.0–1.2 70–84 g/day
Protein quality: animal vs. plant sources

Animal proteins (whey, egg, meat) typically have a higher Digestible Indispensable Amino Acid Score (DIAAS) and greater leucine content, which strongly triggers muscle protein synthesis. Plant proteins can be combined (e.g., rice + beans) to achieve a complete amino acid profile. If you follow a vegan diet, consider increasing your total protein by ~10–20% to compensate for lower digestibility. Our calculator includes a +15% plant‑based adjustment.

Case Study: muscle retention during weight loss

A 75 kg female aims to lose body fat while preserving muscle mass. Using the “fat loss” setting (1.6–2.0 g/kg), she gets 120–150 g protein daily. Combined with resistance training, this high‑protein approach helps maintain lean tissue and enhances satiety, leading to more sustainable weight loss. Our calculator also displays per‑meal targets (e.g., 30–40 g per meal over 4 meals), making practical meal planning easier.

Frequently Asked Questions

For healthy individuals, high protein intake (up to 2.5 g/kg) is considered safe. However, people with pre‑existing kidney disease (e.g., CKD) should consult a physician. Our calculator stays within evidence‑based upper limits (≤2.2 g/kg).

Yes. Legumes, tofu, tempeh, seitan, quinoa, and pulses provide ample protein. Vegans may need slightly higher total intake (≈10–20% more) due to lower digestibility, and our calculator includes a +15% plant‑based adjustment.

Total daily intake is most important. Distributing protein evenly across 3–5 meals (20–40 g per meal) optimizes muscle protein synthesis, especially after exercise.

Pregnancy increases protein needs to ~1.1 g/kg/day in the second and third trimesters. Lactation also raises requirements. Please consult a prenatal care provider for personalized advice.

Moderate protein intake (1.0–1.2 g/kg) is generally safe and may improve glycemic control. However, individuals with diabetic kidney disease should follow nephrologist guidance. This tool is for general healthy populations only.
Evidence‑based methodology — This tool aligns with the Dietary Guidelines for Americans 2025‑2030, EFSA protein recommendations, and ISSN position stand. All coefficients are derived from peer‑reviewed literature. For medical advice, consult a qualified healthcare provider.

Evidence‑based methodology: Our coefficients align with the Dietary Reference Intakes (IOM), ISSN position stand (J Int Soc Sports Nutr, 2017), and recent meta‑analyses. Last updated June 2026.

Primary sources: WHO Protein and Amino Acid Requirements, ISSN position stand: protein and exercise, Morton et al. (2018), Schoenfeld & Aragon (2018) – protein for fat loss.