Protein Intake Calculator

Calculate daily protein grams from body weight, activity level, and fitness goal presets.

Grams of Protein Per Day for Your Weight and Goal

BrainyCalculators editorial insight — unique to this tool

Sedentary adults: ~0.8 g/kg; resistance training: 1.6–2.2 g/kg per ISSN meta-analyses. An 80 kg lifter targets 128–176 g/day — 4 palm-sized chicken portions or equivalent. Elderly need higher per-meal leucine threshold (~2.5 g) to trigger muscle synthesis.

When to use this calculator

Use for protein-specific gram targets. For full macro split, use Macro.

Reference	Value	Context
Sedentary RDA	0.8 g/kg	Minimum
Strength training	1.6–2.2 g/kg	ISSN range
Per meal leucine	~2.5 g	MPS trigger
80 kg lifter	128–176 g	Example range

Balancing protein, carbs, and fats together?

This page targets protein grams only. For full macro split, use the Macro Calculator →

Weight

Unit

Activity Level

Goal

Protein Guidelines (g per kg of body weight)

Goal	Range (g/kg)
Sedentary / Maintain	0.8 – 1.0
Weight Loss	1.2 – 1.6
Active / Muscle Gain	1.6 – 2.2
Athlete / Bodybuilder	2.0 – 3.1

What is Protein Intake?

Protein intake recommendations scale grams per kilogram of body weight by goal: maintenance, fat loss, or muscle gain with training context.

Use this page for the protein slice of nutrition. Macro calculator balances protein, carbs, and fats together; calorie calculator sets total energy first.

Water intake addresses hydration liters per day, not macronutrient grams.

How the Protein Intake Calculator Works

Formula, assumptions, and calculation steps for this health tool.

Methodology

Health calculators use published screening formulas and common planning rules to estimate body, nutrition, pregnancy, or fitness metrics from user inputs.

Calculation Steps

Enter the personal measurements requested by the tool.
Convert height, weight, age, dates, or activity inputs to standard units.
Apply the health or fitness formula for the selected metric.
Show the estimate with practical ranges or interpretation where available.

Assumptions and Limits

Results are educational estimates, not diagnosis or medical advice.
Individual factors such as medication, pregnancy, and medical history can change interpretation.
Consult a clinician for personal health decisions.

Reference basis: Common public-health and sports-science screening formulas.

Real-World Applications

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Muscle Building (Hypertrophy)

Resistance trainers targeting muscle growth need 1.6–2.2 g of protein per kg of body weight daily to maximise muscle protein synthesis. A 80 kg bodybuilder requires 128–176 g/day — typically achieved across 4–6 meals each containing 30–45 g of high-quality protein.

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Fat Loss While Preserving Muscle

Higher protein intakes (2.0–2.4 g/kg/day) are recommended during calorie-deficit weight loss to preserve lean muscle mass — protein's high satiety value also reduces hunger, making adherence to a calorie deficit significantly easier.

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Endurance Athlete Recovery

Endurance athletes (cyclists, marathon runners) need 1.4–1.7 g/kg/day — more than sedentary individuals but less than strength athletes — to repair muscle microdamage from high training volumes and support immune function during heavy training blocks.

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Healthy Ageing & Sarcopenia Prevention

Older adults (65+) are recommended 1.0–1.2 g/kg/day — above the standard RDA of 0.8 g/kg — to counteract age-related muscle loss (sarcopenia). Higher protein intake combined with resistance exercise is the most effective intervention for maintaining muscle mass and functional independence in older age.

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Clinical Nutrition & Recovery

Hospitalised patients, post-surgical patients, and those with pressure ulcers or burn injuries may need 1.5–2.5 g/kg/day to support wound healing and tissue repair — clinical dietitians use protein intake calculations as a core component of nutrition support plans.

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Plant-Based Diet Planning

Vegans and vegetarians must plan protein intake more carefully — plant proteins are typically lower in leucine and have lower digestibility (PDCAAS/DIAAS scores) than animal proteins. Combining complementary sources (legumes + grains) and targeting the higher end of protein recommendations helps ensure adequate essential amino acid intake.

Common Mistakes

Using the wrong body weight for the calculation

Protein recommendations are based on lean body weight or ideal body weight for obese individuals — not total body weight. For someone with 40% body fat, using total bodyweight significantly overestimates protein needs. A more accurate approach uses lean mass (total weight × (1 − body fat %)) as the basis for calculation.

Thinking more protein is always better

Muscle protein synthesis reaches a plateau at approximately 2.2 g/kg/day for most individuals — consuming 3–4 g/kg/day provides no additional muscle-building benefit and simply increases calorie load. For healthy adults, excess dietary protein is oxidised for energy, not stored as additional muscle.

Ignoring protein distribution across meals

Total daily protein matters, but distribution across meals also affects muscle protein synthesis. Consuming 20–40 g of high-quality protein per meal (particularly containing 2–3 g leucine) maximally stimulates muscle protein synthesis at each eating occasion. A single large protein meal cannot compensate for inadequate protein at other meals.

Counting all protein sources equally regardless of quality

Not all protein sources are equivalent. Complete proteins containing all essential amino acids in adequate ratios (animal proteins, soy, quinoa) are more effective for muscle protein synthesis than incomplete plant proteins. The digestibility-corrected amino acid score (DIAAS) reflects a protein source's true nutritional value better than total protein content alone.

Not adjusting intake during calorie restriction

During calorie-deficit dieting, protein requirements increase — the body is more prone to breaking down muscle tissue for energy when calories are limited. Increasing protein to 2.0–2.4 g/kg/day during a weight loss phase helps preserve lean mass, even though total calorie intake is reduced.

Recommended Protein Intake by Goal & Population

Population / Goal	Protein (g/kg/day)	Source
Sedentary adult (minimum)	0.8 g/kg	US RDA / WHO
Active adult (maintenance)	1.2–1.6 g/kg	ISSN / ACSM
Muscle gain (resistance training)	1.6–2.2 g/kg	Morton et al. 2018
Fat loss (muscle preservation)	2.0–2.4 g/kg	Helms et al. 2014
Older adults (65+)	1.0–1.2 g/kg	PROT-AGE Group 2013
Endurance athletes	1.4–1.7 g/kg	Burke et al. / IAAF

References

Morton, R.W. et al. "A Systematic Review, Meta-Analysis and Meta-Regression of the Effect of Protein Supplementation on Resistance Training-Induced Gains in Muscle Mass and Strength." British Journal of Sports Medicine, 2018.
Stokes, T. et al. "Recent Perspectives Regarding the Role of Dietary Protein for the Promotion of Muscle Hypertrophy." Nutrients, 2018.
Institute of Medicine. Dietary Reference Intakes: Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press, 2005.
Helms, E.R. et al. "Evidence-Based Recommendations for Natural Bodybuilding Contest Preparation." Journal of the International Society of Sports Nutrition, 2014.
Bauer, J. et al. "Evidence-Based Recommendations for Optimal Dietary Protein Intake in Older People." JAMDA, 2013.

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