Your numbers aren’t just numbers – they’re insights. BMR shows how much energy your body needs at rest. TDEE tells you how much you burn in a day. BMI indicates body composition, and macros guide what you eat. This page breaks down what each of these means, why it matters, and how to use it to make smarter decisions about your diet, fitness and long-term goals.
Basal Metabolic Rate (BMR) is the number of calories your body burns to keep you alive and functioning at rest – just for breathing, circulation, brain activity, and maintaining body temperature. We calculate your BMR using the Mifflin-St Jeor Equation, which takes into account your age, gender, weight and height – and is considered one of the most accurate formulas used in nutrition science.
Why it matters: Your BMR is the foundation of your calorie needs. It shows how much energy your body requires even if you do absolutely nothing. Understanding your BMR helps you avoid eating too little or too much – and it’s the first step to calculating your TDEE and setting effective goals for weight loss, maintenance or muscle gain.
TDEE is the total number of calories your body burns each day – not just at rest, but also through all your activities like walking, working, exercising, and even digesting food. We calculate your TDEE by multiplying your BMR with an activity multiplier based on your selected lifestyle (from sedentary to very active).
Why it matters: Your TDEE tells you how much to eat to maintain your current weight. To lose fat, you need to eat below your TDEE. To gain muscle, you eat above it. It’s the single most important number when building a calorie-based diet plan – because if you get it wrong, your results will suffer, no matter what you eat.
BMI (Body Mass Index) is a simple ratio of your weight to your height, used to categorise your body size as underweight, normal, overweight, or obese. It’s easy to calculate and widely used in public health to flag potential weight-related risks.
Why it matters: BMI gives you a quick overview of whether your weight is in a generally healthy range. While it doesn’t measure fat or muscle mass, it’s still a helpful starting point – especially when used alongside BMR and TDEE for a fuller picture of your health.
Macronutrients – proteins, fats, and carbohydrates – are the three essential sources of energy your body needs to function, move, and recover. Each plays a unique role in how you feel, perform, and progress towards your fitness goals.
Protein: Essential for building and repairing muscle, supporting immunity, and regulating hormones.
Fats: Important for brain health, hormone production, and long-term energy – not just something to avoid.
Carbohydrates: Your body’s primary fuel source – key for energy, focus, and workout performance.
Why it matters: Calories matter, but where they come from matters more. Tracking your macros gives you control over how your body uses energy – helping you lose fat, gain lean muscle, or simply feel better throughout the day.
Your calorie calculator results are a great start – but they’re not the full picture. Real-life factors like sleep, stress, hormones and even dieting history can significantly impact your metabolism.
Use your numbers as a guide – not a rulebook. Real results come from combining data with awareness of your unique body.
Now that you know your BMR and TDEE, it’s time to apply them. But accuracy, consistency and self-awareness are the keys to meaningful progress.
Common mistakes to avoid:
We answer the most common questions about calorie metrics, how they work, and how to use them to hit your goals.
TDEE (Total Daily Energy Expenditure) includes your BMR plus the calories burned through movement, exercise, and daily activities. It gives a more complete picture of your actual calorie needs.
Macronutrients—protein, carbohydrates, and fats—are the building blocks of your diet. Tracking your macros helps ensure you’re fuelling your body properly for energy, recovery, and overall performance.
Both matter. Calories determine your weight change, but macros influence how your body feels, performs, and recovers. Balancing both leads to better, more sustainable results.
Use BMR and TDEE to set your calorie intake. Then adjust your macros based on your goal—higher protein for muscle gain, lower carbs for fat loss, or balanced for maintenance.