Protein Intake Calculator
How much protein does your body actually need each day?
About Protein Intake Calculator
This calculator estimates your daily protein target using the most direct and evidence-based method: multiplying body weight in kilograms by a goal-specific protein factor. The WHO/FAO/UNU Technical Report Series 935 (2007) establishes the population safe intake at 0.83 g/kg/day for sedentary adults — the minimum to prevent deficiency. Higher multipliers are derived from the International Society of Sports Nutrition (ISSN) Position Stand and meta-analysis evidence for active populations. The result is expressed in grams per day, calories from protein, and a per-meal target to support muscle protein synthesis throughout the day.
Protein (g/day) = Body Weight (kg) x Protein Multiplier (g/kg/day) Goal Multipliers (WHO/FAO/UNU TRS 935 + ISSN evidence): Sedentary Adult 0.83 g/kg/day (WHO population safe level) Weight Loss 1.20 g/kg/day (preserve lean mass in deficit) Active / Fitness 1.40 g/kg/day (support regular training) Muscle Gain 1.80 g/kg/day (hypertrophy stimulus range) Athlete 2.00 g/kg/day (intense or twice-daily training) Elderly (65+) 1.20 g/kg/day (counteract sarcopenia) Protein energy: 1 g protein = 4 kcal Per-meal target: Daily grams / 3 meals
Source: WHO/FAO/UNU Technical Report Series 935 (2007) · ISSN Position Stand: Protein and Exercise (2017, updated 2022) · Morton et al. Br J Sports Med (2018)
Why Your Protein Target Matters
Protein intake that is consistently too low or inappropriately distributed carries measurable health consequences. Getting the target right supports body composition, function, and long-term metabolic health.
Sarcopenia and Muscle Loss
Chronically low protein accelerates age-related muscle loss (sarcopenia). WHO identifies sarcopenia as a major contributor to frailty and loss of independence in older adults. Adequate protein is the single most modifiable dietary factor for preserving lean mass.
Impaired Recovery and Adaptation
Insufficient protein blunts the muscle protein synthesis response to training. Without adequate amino acid availability, resistance and endurance training adaptations are compromised, increasing injury risk and slowing performance gains.
Protein Deficiency Disorders
Severe or prolonged protein deficiency causes kwashiorkor and marasmus — conditions characterised by oedema, immune suppression, and organ dysfunction. Even moderate deficiency impairs wound healing, immune response, and hormone production.
How to Use This Calculator Most Effectively
This result is a practical daily target. Refine it over time based on your progress, training response, and individual health context:
Use lean body mass if you carry significant body fat
Protein requirements are driven by metabolically active tissue, not total mass. Very high body fat can cause this calculator to over-prescribe. In that case, using lean body mass as the input weight gives a more appropriate target.
Distribute protein across meals
Research shows muscle protein synthesis is maximised when protein is spread across 3–4 meals of 20–40 g rather than concentrated in one meal. The per-meal target shown in your result is a useful practical guide.
Prioritise whole-food protein sources
Eggs, fish, lean meat, dairy, legumes, and soy provide protein alongside micronutrients not available in supplements. Supplements can fill gaps but should not replace dietary sources as the primary protein strategy.