Calorie & Macro Calculator
Enter your details to get accurate daily calorie targets and macro breakdowns using the Mifflin-St Jeor formula — the most validated formula in clinical research.
About the Mifflin-St Jeor Formula
The Mifflin-St Jeor equation is the most accurate BMR (Basal Metabolic Rate) formula for most people according to the Academy of Nutrition and Dietetics. Published in 1990, it accounts for age, sex, height, and weight to estimate the number of calories your body needs at complete rest.
Your BMR is then multiplied by an activity factor to get your TDEE (Total Daily Energy Expenditure) — the total calories you burn in a day. From there, we apply a goal-based adjustment:
- Weight loss: −500 calories/day creates approximately 1 lb of fat loss per week
- Maintenance: Eat at TDEE to maintain current weight
- Muscle gain: +500 calories/day supports muscle growth with appropriate training
How to Use Your Results
Your calculated daily calories are a starting point, not a prescription. Individual metabolic rates can vary by 15–20% from formula estimates. Start at the calculated target, track your results for 2–3 weeks, and adjust by 100–200 calories based on actual progress.
For the macro targets, we use evidence-based ratios: ~30% fat, 30% protein, 40% carbohydrates as a baseline, with protein calculated at 1.6g per kg body weight (optimal for muscle preservation during weight loss).
Your calorie needs are just the start. Take our free 2-minute quiz to get a diet recommendation tailored to your exact numbers, goals, and lifestyle.
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