Daily Protein Intake Calculator

International Society of Sports Nutrition (ISSN) & DRI Guidelines

Daily protein requirements vary dramatically based on physical activity, energy balance, and fitness goals:

• Sedentary Baseline: 0.8 g/kg — The minimum intake to prevent nutritional deficiency in inactive adults.

• Endurance Athletes: 1.2 to 1.5 g/kg — Necessary for mitochondrial biogenesis and repair of oxidative muscle damage.

• Hypertrophy & Strength Training: 1.6 to 2.2 g/kg — The optimal scientific range for maximal muscle building.

• Caloric Deficit / Fat Loss: 2.0 to 2.4 g/kg — Elevates thermic effect of food (TEF) and prevents muscle catabolism in an energy deficit.

• The Leucine Threshold: Research shows that consuming 30 to 40 g of high-quality protein per meal provides the 2.5--3.0 g of leucine required to fully activate the mTORC1 signaling pathway for muscle protein synthesis.

How to Use This Calculator

Enter your Unit System — select from Metric (kg), Imperial (lbs), Body Weight (e.g. 75), Primary Fitness Goal / Activity Level — select from Sedentary / Baseline Health (0.8 g/kg RDA), Endurance Runner / Cyclist (1.2–1.5 g/kg), Muscle Building & Hypertrophy (1.6–2.2 g/kg), Target Meals per Day — select from 3 Meals per Day, 4 Meals per Day (Recommended), 5 Meals per Day, and Nutrition Goal Benchmark — select from Custom Goal & Weight, 75 kg Muscle Building (150g Protein / 37.5g per meal), 70 kg Sedentary Adult (56g Protein RDA). Results update instantly — no submit button needed. Use metric or imperial units as labeled. For the most accurate result, measure height and weight in the morning without shoes.

The Formula

Conversion factors (to SI base unit or reference unit):

wt: 75.0

meals: 4.0

Worked Example

An 85 kg lifter on a cutting deficit requires 2.2 g/kg, divided into 4 meals of ~47g protein to maintain strength and maximize fat loss.

Understanding Your Result

Current evidence-based protein recommendations: Sedentary adults: 0.8 g/kg body weight (RDA minimum). Active adults: 1.2–1.6 g/kg. Athletes or those building muscle: 1.6–2.2 g/kg. Older adults (65+): 1.2–1.6 g/kg to counter sarcopenia. The RDA (0.8 g/kg) is the minimum to prevent deficiency — not the optimal intake for body composition or longevity. Protein at each meal (25–40g) maximizes muscle protein synthesis; distribution matters as much as total daily amount.