Macro Calculator
Calculate your ideal protein, carbs, and fat targets based on your body, activity, and goals.
Step 1 of 5
What is your biological sex?
How This Calculator Works
This macro calculator uses a three-step scientific approach to determine your ideal macronutrient targets:
- Basal Metabolic Rate (BMR) — Calculated using the Mifflin-St Jeor equation (Mifflin MD, et al. Am J Clin Nutr. 1990), the most accurate BMR formula validated for modern populations.
- Total Daily Energy Expenditure (TDEE) — Your BMR is multiplied by an activity factor based on the Katch-McArdle activity scale to estimate total daily calorie burn.
- Macro Distribution — Your adjusted calorie target (based on your goal) is split into protein, carbohydrates, and fat using the selected macro ratio. Protein and carbs provide 4 kcal/g; fat provides 9 kcal/g.
Goal adjustments follow evidence-based guidelines: a 500 kcal/day deficit targets approximately 0.45 kg (1 lb) of fat loss per week, while a 300 kcal/day surplus supports lean muscle gain without excessive fat accumulation.
Frequently Asked Questions
What are macros and why do they matter?
Macros (macronutrients) are the three main nutrients your body needs in large amounts: protein, carbohydrates, and fat. Each plays a distinct role — protein builds and repairs tissue, carbs provide energy, and fat supports hormone production and nutrient absorption. Tracking macros gives you more control over body composition than counting calories alone.
Which macro split should I choose?
For general health and weight maintenance, start with "Balanced" (30/40/30). If you're strength training or trying to preserve muscle during a cut, "High Protein" (40/35/25) is a strong choice. "Low Carb" (40/25/35) suits people who feel better with fewer carbohydrates. "Ketogenic" (25/5/70) is for those following a strict keto protocol.
How accurate is this macro calculator?
This calculator uses the Mifflin-St Jeor equation, which a 2005 meta-analysis in the Journal of the American Dietetic Association found to be the most accurate BMR prediction equation for most adults (within 10% for 82% of people). Your actual needs may vary based on genetics, body composition, and metabolic adaptation.
Should I eat the same macros every day?
For simplicity, eating consistent macros daily works well for most people. However, some athletes benefit from carb cycling — eating more carbs on training days and fewer on rest days. The total weekly average matters more than daily precision.
How much protein do I really need?
Research published in the British Journal of Sports Medicine (2018) suggests 1.6-2.2 g/kg of body weight per day for people engaged in resistance training. The "High Protein" split in this calculator typically lands in this range. Sedentary individuals need less — about 0.8 g/kg per day.
Track it effortlessly with AI
KCALM uses AI-powered food recognition to track your calories and macros automatically. Just snap a photo.