Find your ideal daily macronutrient targets — protein, carbohydrates, and fat — based on your calorie needs, activity level, and fitness goal.
Fill in your details, activity level, goal, and diet preference — we will calculate your daily calorie target and recommended protein, carbohydrate, and fat breakdown.
The basics
Macronutrients — or macros — are the three categories of nutrients that provide your body with energy: protein, carbohydrates, and fat. Unlike micronutrients (vitamins and minerals), which are needed in small amounts, macros make up the bulk of what you eat and directly determine how many calories you consume.
The calculator first estimates your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation — the most validated formula for predicting resting calorie burn. BMR is then multiplied by an activity factor to give your Total Daily Energy Expenditure (TDEE). Your calorie target is adjusted up or down based on your goal, and the resulting calories are split into protein, carbohydrates, and fat grams according to your chosen diet preference.
Protein is the structural macro — it provides the amino acids your body needs to build and maintain muscle, produce enzymes, and make hormones. It also happens to be the most satiating macro per calorie.
Carbohydrates are your body's preferred energy source, especially during exercise. They are stored as glycogen in the liver and muscles, providing fast, accessible fuel. Fibre — a type of carbohydrate — also feeds gut bacteria and supports digestion.
Fat is calorie-dense but essential. It supports the production of steroid hormones (including testosterone and oestrogen), enables absorption of vitamins A, D, E, and K, and provides a slow-burning energy source during lower-intensity activity. Essential fatty acids — omega-3 and omega-6 — cannot be made by the body and must come from food.
For fat loss, the macro calculator applies a 15% calorie deficit to your TDEE and shifts the macro split towards higher protein. A protein intake of 35–40% of calories helps preserve lean muscle while you lose weight, keeping your metabolic rate higher and making it easier to stay in a deficit without losing strength. Keep carbs moderate to sustain training performance and use fat to fill the remaining calories.
For muscle gain, the calculator applies a 10% calorie surplus — enough to support growth without excessive fat gain. Protein stays high at around 30–35% of calories to maximise muscle protein synthesis. Carbohydrates increase to 40–45% because they fuel resistance training and drive the insulin response that helps shuttle nutrients into muscle cells. Fat makes up the remainder.
Calories determine whether you gain, lose, or maintain weight. Macros determine body composition — the ratio of muscle to fat — within that weight change. You can lose weight eating only carbohydrates if your calories are low enough, but you will lose muscle alongside fat. Tracking macros is a more precise tool that serves your physique and performance goals, not just the number on the scale.
Example macro splits
Balanced
Higher Protein
Lower Carb
Calorie density reference
FAQ
Macros — short for macronutrients — are the three main nutrients your body needs in large amounts: protein, carbohydrates, and fat. Each provides calories and serves specific roles. Protein builds and repairs tissue; carbohydrates are your primary energy source; fat supports hormones, brain function, and fat-soluble vitamins. Tracking macros means monitoring how many grams of each you eat daily.
Start by estimating your Total Daily Energy Expenditure (TDEE) using your age, sex, height, weight, and activity level. Then adjust calories for your goal (cut, maintain, or bulk) and divide those calories across protein, carbohydrates, and fat based on your preferred ratio. This calculator does all of that automatically.
A higher-protein split works well for fat loss — something like 35–40% protein, 25–35% carbs, and 25–30% fat. The extra protein helps preserve muscle in a deficit and keeps hunger lower. Total calorie intake still drives fat loss; the macro split shapes your body composition while you lose.
Most people aiming to lose fat or build muscle benefit from 1.6–2.2 g of protein per kilogram of body weight per day. The macro calculator targets around 30–40% of calories from protein and pairs it with the Protein Calculator on this site for a more detailed per-kilogram figure.
Carbohydrates are not inherently fattening. What drives fat gain is eating more total calories than you burn. That said, reducing carbs — particularly refined sugars and white starches — can help control appetite and make hitting a calorie deficit easier for many people. The right carb intake depends on your preferences, activity level, and how your body responds.
Macro tracking can be a powerful tool for body composition goals, especially when progress has stalled. It creates awareness of what you are eating without needing perfection. You do not have to track forever — even a few weeks of logging can teach you portion sizes and nutrient density, making it easier to eat intuitively later.
Counting macros is a layer on top of counting calories — it tells you not just how much energy you are eating, but where it comes from. If your only goal is weight change, calorie counting alone can work. If you care about body composition, performance, or satiety, tracking macros gives you finer control.
A moderate split with extra protein and carbs suits muscle gain well — roughly 30–35% protein, 40–45% carbs, and 20–25% fat, combined with a small calorie surplus of around 10%. Carbohydrates fuel training sessions and support recovery, while protein provides the amino acids needed for muscle protein synthesis.
Dietary fat does not automatically become body fat. Fat is calorie-dense at 9 kcal per gram — more than double protein or carbs — which means it is easy to overeat. In the context of a controlled calorie intake, healthy fats from nuts, olive oil, avocado, and oily fish are beneficial. Avoiding fat to the point where hormones and micronutrient absorption suffer is counterproductive.
The calculator uses the Mifflin-St Jeor equation to estimate BMR and applies a standard activity multiplier for TDEE. This is one of the most validated approaches available without lab testing, with an accuracy of plus or minus 10–15% for most people. Treat the result as a starting point and adjust based on real-world progress over two to three weeks.
Keep exploring
Macros are one piece of the picture. These free Fitlydoo tools cover the rest of your numbers.
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