health
BMI Calculator
Calculate your Body Mass Index instantly.
Macro Calculator
Calculate your Total Daily Energy Expenditure (TDEE) and optimal macronutrient breakdown based on your weight, height, age, activity level, and fitness goal.
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How to use the Macro Calculator
Enter your stats
Choose metric or imperial, then enter your age, gender, height, and weight. These are used to calculate your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation.
Select your activity level
Choose the activity level that best matches your typical week. Each option includes a description to help you decide. This multiplies your BMR to produce your Total Daily Energy Expenditure (TDEE).
Set your goal
Choose between Lose Weight (−500 calorie deficit), Maintain Weight (at TDEE), or Build Muscle (+300 calorie surplus). Your daily calorie target and macro breakdown update immediately.
Read your macro breakdown
Your recommended daily calories appear as a hero number. The three macro cards below show grams, calories, and percentage for protein, carbohydrates, and fat. The donut chart visualises the macro split.
About this Macro Calculator
Macronutrients — protein, carbohydrates, and fat — are the three energy-providing nutrients in food. Tracking them gives you precise control over your diet beyond just counting calories. Our macro calculator starts from your TDEE (Total Daily Energy Expenditure) and works backwards to give you a personalised daily calorie target and macro split based on your goal. The BMR (Basal Metabolic Rate) is calculated using the Mifflin-St Jeor equation, the most widely validated formula for estimating resting energy expenditure. Your TDEE is then calculated by multiplying your BMR by an activity factor. The calorie target is adjusted by ±300–500 calories depending on your goal. Protein targets are set higher during a calorie deficit (2.2g per kg of bodyweight) to help preserve muscle mass while losing fat, and at 2.0g/kg during maintenance and muscle gain phases. Fat is set at 25% of total calories to support hormonal function, with carbohydrates filling the remainder. These are evidence-based starting points — individual requirements vary, and a registered dietitian can refine these targets for your specific needs.
Frequently Asked Questions
Macronutrients (macros) are the three main nutrient groups: protein (4 cal/g), carbohydrates (4 cal/g), and fat (9 cal/g). Tracking macros gives you more granular control over your diet than just counting calories.
General recommendations range from 0.7–1g of protein per pound of bodyweight (1.5–2.2g per kg) for active individuals looking to build or preserve muscle. The exact amount depends on your goals and activity level.
TDEE (Total Daily Energy Expenditure) is the total number of calories your body burns in a day, including your resting metabolic rate and all physical activity. Eating at your TDEE maintains weight; below it creates a deficit for fat loss.
For fat loss, set a moderate calorie deficit (typically 300–500 calories below TDEE) and keep protein high — around 2.2g per kg of bodyweight — to preserve muscle. Fat should cover at least 20–25% of calories for hormonal health, with carbohydrates filling the remainder. Our macro calculator applies these ratios automatically when you select 'Lose Weight'.
BMR (Basal Metabolic Rate) is the calories your body burns at complete rest — just to keep your organs functioning. TDEE is your BMR multiplied by an activity factor to account for all the calories you burn through movement and exercise. Most people should eat close to their TDEE to maintain weight, not their BMR.
The scientific consensus for muscle growth is 1.6–2.2g of protein per kg of bodyweight per day. Our macro calculator uses 2.0g/kg for muscle gain and maintenance, which is a practical target that maximises muscle protein synthesis without excessive intake. Spreading protein across 3–4 meals maximises uptake per meal.