Calculate your Basal Metabolic Rate and Daily Energy Expenditure
Male
Female
Sedentary (Office job, little exercise)
Lightly Active (Light exercise 1-3 days/week)
Moderately Active (Moderate exercise 3-5 days/week)
Very Active (Hard exercise 6-7 days/week)
Extra Active (Very hard physical job or 2x training)
Your Daily Requirements
Basal Metabolic Rate (BMR):0 kcal
Total Daily Energy Expenditure (TDEE):0 kcal
Daily Macronutrient Split (Maintenance)
Protein
0g
Carbs
0g
Fats
0g
function calculateDietMetrics() {
var gender = document.getElementById("diet_gender").value;
var age = parseFloat(document.getElementById("diet_age").value);
var weight = parseFloat(document.getElementById("diet_weight").value);
var height = parseFloat(document.getElementById("diet_height").value);
var activity = parseFloat(document.getElementById("diet_activity").value);
if (isNaN(age) || isNaN(weight) || isNaN(height)) {
alert("Please enter valid numbers for age, weight, and height.");
return;
}
// Mifflin-St Jeor Equation
var bmr = 0;
if (gender === "male") {
bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5;
} else {
bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161;
}
var tdee = bmr * activity;
// Macro Logic: 30% Protein, 40% Carbs, 30% Fat
// Protein: 4 kcal/g, Carbs: 4 kcal/g, Fat: 9 kcal/g
var proteinGrams = (tdee * 0.30) / 4;
var carbGrams = (tdee * 0.40) / 4;
var fatGrams = (tdee * 0.30) / 9;
document.getElementById("res_bmr").innerText = Math.round(bmr).toLocaleString() + " kcal/day";
document.getElementById("res_tdee").innerText = Math.round(tdee).toLocaleString() + " kcal/day";
document.getElementById("res_protein").innerText = Math.round(proteinGrams) + "g";
document.getElementById("res_carbs").innerText = Math.round(carbGrams) + "g";
document.getElementById("res_fats").innerText = Math.round(fatGrams) + "g";
document.getElementById("diet_results").style.display = "block";
}
Understanding Dietician Calculations: BMR and TDEE
Nutrition science relies heavily on clinical mathematics to determine an individual's specific energy needs. Whether you are looking to lose weight, gain muscle, or maintain your current physique, everything starts with two core metrics: BMR and TDEE.
What is BMR (Basal Metabolic Rate)?
Your Basal Metabolic Rate is the number of calories your body requires to perform basic life-sustaining functions while at complete rest. This includes breathing, blood circulation, cell production, and nutrient processing. Essentially, if you stayed in bed all day and didn't move a muscle, your BMR is what you would burn.
Our calculator uses the Mifflin-St Jeor Equation, which is currently considered the most accurate standard for predicting BMR in healthy adults. The formula accounts for gender, weight, height, and age to provide a baseline for your metabolic health.
What is TDEE (Total Daily Energy Expenditure)?
TDEE is an estimation of how many calories you burn per day when exercise and physical activity are factored in. This is the "maintenance" number. If you consume exactly this amount of calories, your weight should remain stable.
Sedentary: Desk jobs with very little movement.
Moderately Active: Most people who hit the gym 3-4 times a week fall into this category.
Very Active: Individuals with physical labor jobs or those training for endurance events.
Calculating Your Macronutrients
Calorie counting is only half the battle; the source of those calories matters for body composition. A standard dietician-approved "Balanced" split usually looks like this:
Protein (30%): Vital for muscle repair and satiety. Contains 4 calories per gram.
Carbohydrates (40%): The primary energy source for your brain and muscles. Contains 4 calories per gram.
Fats (30%): Essential for hormone production and nutrient absorption. Contains 9 calories per gram.
Example Calculation
Consider a 30-year-old male, weighing 80kg at 180cm tall with a moderately active lifestyle: