Calculate your optimal daily protein intake based on weight, body fat, activity level, and goals. Includes per-meal targets, leucine thresholds, and food source reference.
Protein is the most important macronutrient for body composition, satiety, and metabolic health. It provides the amino acid building blocks for muscle, bone, enzymes, hormones, and immune cells. Yet the government RDA of 0.8 g/kg (about 0.36 g/lb) — established to prevent deficiency, not to optimize health — is now widely considered inadequate by sports nutrition researchers and health organizations for virtually anyone who exercises.
This Daily Protein Calculator computes your optimal intake using evidence-based targets from the International Society of Sports Nutrition (ISSN), American College of Sports Medicine (ACSM), and the PROT-AGE study group. It accounts for your total body weight or lean body mass (when body fat is provided), activity level, and specific goals — ranging from sedentary (0.8 g/kg) to fat loss during a caloric deficit (2.0 g/kg).
Beyond a single number, the calculator shows per-meal protein distribution to meet the leucine threshold (~2.5g leucine per meal) that maximally stimulates muscle protein synthesis. It includes a protein-rich food table sorted by protein density (grams per 100 calories), leucine content data for common protein sources, and a side-by-side comparison of targets across all goal categories. Whether you are building muscle, cutting body fat, or maintaining health as you age, this tool gives you an actionable, personalized target.
Most people undereat protein, especially during fat loss when muscle preservation is critical. This calculator provides a goal-specific target, distributes it across meals for optimal muscle protein synthesis, and includes food sources ranked by protein density to make meal planning practical. Keep these notes focused on your operational context. Tie the context to the calculator’s intended domain.
Protein (g/day) = Body Weight (kg) × Target (g/kg). Targets: Sedentary 0.8, General 1.2, Muscle building 1.6, Endurance 1.4, Fat loss 2.0, Elderly 1.2 g/kg. If lean body mass available: Protein = LBM (kg) × Target × 1.1. Per meal = Total / number of meals. Leucine threshold: ≥2.5g leucine per meal ≈ ≥25g protein from animal sources.
Result: 131 g/day (33 g per meal × 4)
A 180 lb (81.6 kg) individual targeting muscle building uses 1.6 g/kg × 81.6 = 131 g/day. Divided across 4 meals: 33g each, which exceeds the leucine threshold (≈25g) for maximal muscle protein synthesis at each meal.
Research suggests the body prioritizes protein intake, adjusting total calorie consumption to meet a protein target. On low-protein diets, people overeat carbs and fats seeking adequate protein — a phenomenon called "protein leverage." Increasing protein percentage from 15% to 25% of calories reduces spontaneous calorie intake by ~10%, making high-protein diets powerful for appetite control and fat loss.
The Protein Digestibility-Corrected Amino Acid Score (PDCAAS) rates protein quality based on amino acid profile and digestibility. The newer Digestible Indispensable Amino Acid Score (DIAAS) measures ileal digestibility of individual amino acids — a more accurate method. Whey, egg, and casein score 1.0 (perfect) on PDCAAS. Soy scores 0.91. Rice 0.42 and pea 0.67 individually, but combined they approach 1.0. For practical purposes, animal proteins are complete; plant proteins should be combined over the day.
After consuming a protein-rich meal, muscle protein synthesis (MPS) peaks at ~90 minutes and returns to baseline by ~3 hours, even if amino acid levels remain elevated. This "muscle-full" or "refractory period" means that spacing protein across 4–5 meals (every 3–4 hours) is more effective for total daily MPS than loading protein into 1–2 meals, even at the same total intake.
The optimal range depends on your goal: 0.8 g/kg (sedentary minimum), 1.2–1.6 g/kg (active adults and muscle building), up to 2.0+ g/kg (caloric deficit to preserve muscle). For most active people, 0.7–1.0 g per pound of body weight is a practical guideline.
No — in healthy individuals, there is no evidence that high protein intake (up to 2.5+ g/kg) damages kidneys. A 2018 meta-analysis found no adverse renal effects. However, people with pre-existing kidney disease should follow their nephrologist's guidance.
If you have a normal body fat percentage (15–25%), total body weight works fine. If you carry significant excess body fat (>30%), using lean body mass gives a more accurate target and avoids overestimating needs.
Total daily intake matters most, but distributing protein evenly across 3–5 meals (≥25g each) optimizes muscle protein synthesis. Post-workout protein within 2 hours is beneficial but less critical than previously believed if total intake is adequate.
Yes. Plant proteins have slightly lower leucine content and digestibility (PDCAAS/DIAAS), so aim for 10–20% more total protein (e.g., 1.8–2.0 g/kg). Combine complementary sources (rice + pea, legumes + grains). Soy, tempeh, and seitan are high-quality plant proteins.
The leucine threshold is the minimum leucine intake per meal (~2.0–2.5g) needed to maximally stimulate muscle protein synthesis. This corresponds to about 25–30g of animal protein or 35–40g of plant protein per meal. Whey protein has the highest leucine content per gram.