Protein Intake Calculator
Calculates your optimal daily protein intake in grams based on body weight, body fat percentage, training frequency, and goal. Use it when setting up a diet plan for muscle building, fat loss, or general health.
About this calculator
Protein requirements vary significantly depending on whether your goal is sedentary health maintenance, muscle building, or fat loss. This calculator first estimates lean body mass when body fat percentage is provided: Lean Mass = Weight × (1 − Body Fat% ÷ 100). A base multiplier is then applied to lean mass (or total body weight if no body fat data is entered): 0.8 g/kg for sedentary, 1.6 g/kg for maintenance, 2.2 g/kg for building muscle, 2.4 g/kg for cutting, and 2.0 g/kg for general performance. An additional training bonus of 0.05 g/kg is added per training day per week to reflect the elevated protein demands of frequent exercise: Final Multiplier = Base Multiplier + (Training Days × 0.05). Basing the calculation on lean mass rather than total body weight gives more accurate targets for people with higher body fat percentages.
How to use
Example: 85 kg person, 20% body fat, goal = build muscle, training 4 days/week. Step 1 — Lean mass: 85 × (1 − 20/100) = 85 × 0.8 = 68 kg. Step 2 — Base multiplier for 'build': 2.2 g/kg. Step 3 — Training bonus: 4 × 0.05 = 0.20. Step 4 — Final multiplier: 2.2 + 0.20 = 2.4 g/kg. Step 5 — Daily protein: 68 × 2.4 = 163 g/day. This person should aim for approximately 163 grams of protein daily to support muscle growth.
Frequently asked questions
How much protein per day do I need to build muscle effectively?
Research consistently shows that 1.6–2.2 g of protein per kg of body weight per day is the effective range for maximizing muscle protein synthesis in people who resistance train. This calculator uses 2.2 g/kg as the baseline for a muscle-building goal, with an additional 0.05 g/kg added per weekly training day. Distributing this protein across 4–5 meals — aiming for roughly 30–40 g per meal — optimizes the muscle-building stimulus throughout the day. Consuming more than approximately 2.6 g/kg/day provides no additional muscle-building benefit for most people, though it remains safe.
Should I calculate protein based on total body weight or lean body mass?
Using lean body mass gives more accurate and typically lower targets for people with higher body fat levels, since adipose tissue has minimal protein requirements compared to muscle. For a 100 kg person at 35% body fat, calculating protein on total weight would produce a target roughly 40% higher than a lean-mass-based calculation. This calculator automatically switches to lean-mass-based calculations when you provide a body fat percentage. If you do not know your body fat percentage, the calculator uses a conservative estimate of 15% body fat to approximate lean mass.
Why does training frequency affect how much protein I need each day?
Each resistance training session creates microscopic damage to muscle fibers that requires amino acids for repair and growth — a process called muscle protein synthesis that remains elevated for 24–48 hours after exercise. Training more frequently means more concurrent repair processes are active at any given time, increasing the total daily protein demand. This calculator adds 0.05 g/kg of body weight per weekly training day on top of the base multiplier to reflect this. Someone training 6 days per week will therefore have a meaningfully higher protein target than someone training 2 days per week at the same body weight and goal.