Daily Protein Needs Calculator
Calculate how much protein you need per day based on body weight and activity level.
How to use this tool
- Enter body weight and activity / goal in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your min protein and the full breakdown beneath it.
Most adults need 0.8–2.0 g of protein per kg of body weight per day, depending on activity level. Athletes and strength trainers need more.
⚠ This tool is for general information and education only and is not medical advice. Consult a qualified healthcare professional before making health decisions.
Formula
Minimum protein (g/day) = round( body weight (kg) × activity multiplier )
Maximum protein (g/day) = round( body weight (kg) × (activity multiplier + 0.4) )
How it works
The calculator multiplies body weight in kilograms by a user-selected activity/goal multiplier (in g/kg) to produce the lower bound of the recommended daily protein range, then adds 0.4 g/kg to produce the upper bound. The range reflects the fact that protein needs span a band rather than a single point, with the optimal amount depending on training intensity, recovery goals, and individual metabolism. Values are rounded to whole grams.
Worked example
- Body weight = 70 kg, Activity multiplier = 1.2 g/kg.
- Minimum protein = round(70 × 1.2) = round(84) = 84 g/day.
- Maximum protein = round(70 × (1.2 + 0.4)) = round(70 × 1.6) = round(112) = 112 g/day.
Protein range: 84 – 112 g/day
Common mistakes to avoid
- Entering body weight in pounds when the formula uses kilograms, producing a protein target 2.2x too high.
- Choosing the wrong activity level — 'active' typically means structured exercise 4-5 days per week, not a physically demanding job, so misclassification shifts the multiplier.
- Distributing all protein in one or two large meals rather than spreading it across 3-4 meals, which limits muscle protein synthesis per meal.
Key terms
- Protein multiplier (g/kg)
- The grams of protein recommended per kilogram of body weight per day; ranges from about 0.8 g/kg for sedentary adults to 2.0+ g/kg for strength athletes.
- Lean body mass
- Body weight minus fat mass; protein needs are sometimes calculated on lean mass rather than total body weight for greater precision.
- Nitrogen balance
- The difference between nitrogen consumed (from dietary protein) and nitrogen excreted; a positive balance supports muscle growth.
- Essential amino acids
- The nine amino acids the body cannot synthesise and must obtain from food; high-quality protein sources contain all nine.
- Protein synthesis
- The cellular process of building new proteins from amino acids, stimulated by dietary protein intake and resistance exercise.
Frequently asked questions
- How much protein do I need per day?
- The minimum RDA is 0.8 g/kg/day. Active people and those building muscle typically benefit from 1.2–2.0 g/kg/day. Most high-quality research suggests 1.6 g/kg is sufficient to maximise muscle protein synthesis.
- Does it matter when I eat protein?
- Spreading protein across 3–4 meals of 25–40 g each maximises muscle protein synthesis compared to eating it all at once.