How much protein should I eat?

For active adults, research supports 1.6–2.2 g of protein per kg of body weight per day. Higher intakes (up to 2.4 g/kg) help preserve lean mass during a calorie deficit.

How are macros calculated from calories?

Protein is set in g per kg of body weight, fat as a percentage of total calories (typically 20–35%), and carbohydrate fills the remaining calories. Protein and carbs contain 4 kcal per gram; fat contains 9 kcal per gram.

Should macros change when cutting or bulking?

Yes. In a deficit, keep protein higher (around 2.0–2.4 g/kg) to preserve muscle. In maintenance or a surplus, 1.6–2.0 g/kg is generally sufficient. Fat and carbohydrate adjust with total calorie target.

Macro Calculator — Protein, Carbs, and Fat from TDEE

About this calculation

This calculator estimates your daily macronutrient targets in three steps. First it computes Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation, then multiplies by an activity factor (1.2–1.9) to get Total Daily Energy Expenditure (TDEE). Finally, it adjusts for your goal and splits the resulting calories into protein, fat, and carbohydrate.

Protein

Protein is set per kilogram of body weight — the most evidence-supported approach. Systematic reviews (Morton et al., 2018; Phillips & Van Loon, 2011) suggest 1.6–2.2 g/kg/day for active adults seeking to maintain or build lean mass. During a calorie deficit, higher intakes help preserve muscle, so this calculator uses 2.2 g/kg for steady or rapid weight loss, 2.0 g/kg for gentle weight loss, and 1.8 g/kg for maintenance and weight-gain goals.

Fat

Fat is set as a percentage of total calories. The Institute of Medicine's Acceptable Macronutrient Distribution Range (AMDR) for fat is 20–35% of energy. This calculator uses 25% for all weight-loss and weight-gain goals, and 30% for maintenance. A lower bound of around 0.5–0.8 g/kg is often cited for hormonal health.

Carbohydrate

Carbohydrate fills the remaining calories after protein and fat are allocated. Energy densities are 4 kcal/g for protein and carbohydrate and 9 kcal/g for fat (Atwater factors).

Goals

Weight-loss goals (rapid / steady / gentle) subtract 750, 500, or 250 kcal/day from TDEE — roughly 1.5 / 1 / 0.5 lb per week under the Wishnofsky approximation. Weight-gain goals add 250 or 500 kcal/day. Real-world results vary with adherence, metabolic adaptation, training status, and other factors.

Medical disclaimer. This calculator is for general educational use and is not medical advice, diagnosis, or treatment. Macro targets shown here are estimates based on population averages and do not account for medical conditions, medications, pregnancy, kidney disease, history of disordered eating, or individual needs. Consult a qualified healthcare professional or registered dietitian before making significant changes to your diet — especially if you are under 18, pregnant or breastfeeding, have a chronic condition, or have a history of eating disorders.