Athlete Nutrition Calculator

The Athlete Nutrition Calculator estimates your Total Daily Energy Expenditure (TDEE) and macronutrient requirements based on body metrics, sex, activity level, and training goals. This tool helps athletes optimize performance, recovery, and body composition. Whether you're cutting for competition, building muscle in the off-season, or fueling for endurance, this tool provides a science-backed nutritional roadmap.

Athlete’s chronological age (13-80 years)
Sex assigned at birth for metabolic calculations
Athlete’s current body weight (66-551 lbs)
Average weekly training load
Primary nutritional objective

How Total Daily Energy Expenditure (TDEE) Is Calculated

Total Daily Energy Expenditure represents the total calories you burn per day, combining the energy needed at rest and the energy burned through activity. This calculator first converts your imperial inputs (lbs, feet/inches) to metric units to apply the standard Mifflin–St Jeor equation.

The Mifflin–St Jeor Equation

BMR = (10 × W) + (6.25 × H) − (5 × A) + S

Where:

  • W = Weight in kilograms (lbs ÷ 2.205)
  • H = Height in centimeters ([ft × 30.48] + [in × 2.54])
  • A = Age in years
  • S = Sex (+5 for Male, -161 for Female)

Once your Basal Metabolic Rate (BMR) is found, we multiply it by an activity factor based on your training load (ranging from 1.2 for sedentary to 1.9 for elite athletes). Finally, we adjust this number by +15% for muscle gain or -15% for fat loss to find your target calories.

What Your Calculation Mean

Your Calculation provide a specific roadmap for daily intake. The macronutrient split aims to help you prioritize protein for muscle repair and carbohydrates for training energy.

For Fat Loss:

Your target calories create a moderate deficit. Prioritize high protein (2.0g per kg of bodyweight) to preserve muscle mass while in a caloric deficit.

To Maintain:

These calories match your energy output. Focus on balanced macros with 1.6g of protein per kg to support recovery and performance.

For Muscle Gain:

You are in a caloric surplus. Ensure you hit 2.2g of protein per kg and consume ample carbohydrates to fuel intense training sessions.

Calculation logic verified using publicly available standards.

View our Accuracy & Reliability Framework →