Macros Calculator
Find your daily protein, carbohydrate and fat targets based on your body, activity level and goal. Free, instant, works worldwide.
About This Macros Calculator
This free macros calculator uses the Mifflin-St Jeor equation, the most accurate formula for estimating basal metabolic rate (BMR) in most adults, to calculate your total daily energy expenditure (TDEE). It then adjusts your calorie and macronutrient targets based on your specific goal, whether that is losing weight, building muscle, or maintaining your current body composition.
Macronutrients are the three main categories of nutrients that provide energy: protein, carbohydrates and fat. Each gram of protein provides 4 calories, each gram of carbohydrate provides 4 calories, and each gram of fat provides 9 calories. The ratio of these three macros in your diet has a significant impact on how your body uses energy, recovers from exercise, and changes in composition over time.
For weight loss, the calculator applies a moderate calorie deficit while prioritising a higher protein intake to preserve lean muscle mass. For muscle gain, a modest calorie surplus is applied with increased protein and carbohydrates to support training recovery and growth. For maintenance, macros are distributed to support energy balance and general health. All three approaches are based on widely used evidence-based nutritional guidelines.
These targets are a starting point, not a prescription. Individual responses to nutrition vary considerably. If you have a medical condition, are pregnant or breastfeeding, or have specific health goals, always consult a registered dietitian or healthcare provider before making significant changes to your diet.
Frequently Asked Questions
Macronutrients, or macros, are the three nutrients your body uses for energy: protein, carbohydrates and fat. Protein supports muscle repair and satiety, carbohydrates are the primary fuel for your brain and muscles during exercise, and fat supports hormone production, brain function and the absorption of fat-soluble vitamins. Tracking macros gives you more precise control over your body composition than simply counting calories alone.
This calculator uses the Mifflin-St Jeor equation to calculate your basal metabolic rate (BMR), which is how many calories your body needs at complete rest. Your BMR is then multiplied by an activity factor to get your total daily energy expenditure (TDEE). Your macro targets are then calculated from your adjusted calorie goal based on your chosen objective.
General guidance from sports nutrition research suggests 1.6 to 2.2 grams of protein per kilogram of body weight for people who exercise regularly. For weight loss, higher protein intake (around 2.0 to 2.4 g per kg) helps preserve muscle mass during a calorie deficit. For maintenance or muscle gain, 1.6 to 2.0 g per kg is typically sufficient. Sedentary individuals need considerably less, around 0.8 g per kg.
TDEE stands for Total Daily Energy Expenditure. It is the total number of calories your body burns in a day, including your resting metabolic rate, the energy used during physical activity, and the thermic effect of food (the energy used to digest meals). It is calculated by multiplying your BMR by an activity multiplier ranging from 1.2 (sedentary) to 1.9 (extremely active).
A moderate deficit of 300 to 500 calories below your TDEE is generally recommended for sustainable fat loss without excessive muscle loss. This typically produces a loss of approximately 0.3 to 0.5 kg per week. More aggressive deficits are possible but increase the risk of muscle loss, nutrient deficiencies, and metabolic adaptation. This calculator applies a 400-calorie deficit for the weight loss goal.
Consistency over the week matters more than hitting exact numbers every single day. Many people use a flexible approach, eating slightly more carbohydrates on training days and slightly more fat on rest days, while keeping protein consistent. What is most important is that your weekly average aligns with your targets. Rigid daily tracking can be useful early on, but a more relaxed approach tends to be more sustainable long-term.