Free Nutrition Calculator

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Free Nutrition & Macro Calculator

Calculate your daily calorie needs and macronutrient breakdown instantly.

Male Female
Sedentary (Little or no exercise) Lightly Active (Exercise 1-3 days/week) Moderately Active (Exercise 3-5 days/week) Very Active (Hard exercise 6-7 days/week) Extra Active (Very hard exercise & physical job)
Maintain Weight Weight Loss (-500 cal/day) Weight Gain (+500 cal/day)

Your Personalized Nutrition Plan

0
Daily Calories (kcal)
PROTEIN
0g
CARBS
0g
FATS
0g

Understanding Your Daily Nutrition Needs

Managing your health starts with understanding energy balance. This free nutrition calculator uses the Mifflin-St Jeor Equation, widely considered the most accurate method for estimating Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE).

How the Calculation Works

The calculator first determines your BMR—the number of calories your body burns at rest to maintain vital functions. Then, it applies an activity multiplier based on your lifestyle and adjusts the total based on your fitness goals (weight loss, maintenance, or muscle gain).

Balanced Macronutrient Breakdown

To ensure your energy comes from the right sources, we use a balanced ratio optimized for general health and performance:

  • Protein (30%): Vital for muscle repair and satiety. Contains 4 calories per gram.
  • Carbohydrates (40%): Your body's primary fuel source for workouts and brain function. Contains 4 calories per gram.
  • Fats (30%): Essential for hormone production and nutrient absorption. Contains 9 calories per gram.

Real-World Example

Imagine a 30-year-old male weighing 80kg and 180cm tall with a "Moderately Active" lifestyle. His maintenance calories would be approximately 2,700 kcal. If his goal is weight loss, the calculator would recommend roughly 2,200 kcal per day, distributed as follows: 165g of protein, 220g of carbohydrates, and 73g of fats.

Tips for Success

While this nutrition calculator provides a scientific starting point, remember that nutrition is personal. Track your progress for 2-3 weeks. If you aren't seeing results, adjust your intake by 100-200 calories. Always prioritize whole foods, lean proteins, and plenty of fiber to maximize the benefits of your calculated plan.

function calculateNutrition() { var gender = document.getElementById("nutriGender").value; var age = parseFloat(document.getElementById("nutriAge").value); var weight = parseFloat(document.getElementById("nutriWeight").value); var height = parseFloat(document.getElementById("nutriHeight").value); var activity = parseFloat(document.getElementById("nutriActivity").value); var goal = document.getElementById("nutriGoal").value; if (isNaN(age) || isNaN(weight) || isNaN(height) || age <= 0 || weight <= 0 || height <= 0) { alert("Please enter valid positive numbers for age, weight, and height."); return; } // Basal Metabolic Rate (BMR) – Mifflin-St Jeor Equation var bmr; if (gender === "male") { bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5; } else { bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161; } // Total Daily Energy Expenditure (TDEE) var tdee = bmr * activity; // Adjust for Goal var finalCalories; if (goal === "lose") { finalCalories = tdee – 500; } else if (goal === "gain") { finalCalories = tdee + 500; } else { finalCalories = tdee; } // Ensure calories don't go too low for health reasons if (finalCalories < 1200) finalCalories = 1200; // Macronutrient Calculation (30% P, 40% C, 30% F) var proteinGrams = (finalCalories * 0.30) / 4; var carbsGrams = (finalCalories * 0.40) / 4; var fatsGrams = (finalCalories * 0.30) / 9; // Display Results document.getElementById("resCalories").innerText = Math.round(finalCalories).toLocaleString(); document.getElementById("resProtein").innerText = Math.round(proteinGrams) + "g"; document.getElementById("resCarbs").innerText = Math.round(carbsGrams) + "g"; document.getElementById("resFats").innerText = Math.round(fatsGrams) + "g"; document.getElementById("nutriResult").style.display = "block"; // Smooth scroll to result document.getElementById("nutriResult").scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }

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