Free tool · No login
Estimate your daily calories and protein, carb, and fat targets using the Mifflin-St Jeor equation — the same BMR method used by coaches and nutrition apps worldwide.
Sex
Units
Goal
Daily target
2693
kcal / day
Estimates use the Mifflin-St Jeor equation. Not medical advice — consult a professional for personalized nutrition.
Enter your age, sex, height, weight, activity level, and goal — cut, maintain, or bulk. The calculator runs the Mifflin-St Jeor equation to estimate your basal metabolic rate (BMR), then multiplies it by an activity factor to produce your total daily energy expenditure (TDEE). From there, it applies a goal-specific calorie adjustment and splits your intake into protein, carbohydrates, and fat.
Protein is set per kilogram of body weight — higher when cutting to protect lean mass, moderate when maintaining, and slightly lower when bulking since total calories are already elevated. Fat is allocated at roughly 27% of calories for hormonal health and satiety. Remaining calories fill your carb target, which fuels training and recovery.
This tool is built for lifters, runners, and anyone starting a structured nutrition plan who wants a data-backed starting point without paying for a coach or signing up for an account. Whether you are prepping for a meet, dialing in race-week fueling, or simply trying to eat enough protein, the calculator gives you clear gram targets you can log immediately.
It works best for healthy adults aged 18 and older. If you are pregnant, managing a medical condition, or working with a registered dietitian, use these numbers as a reference — not a prescription.
Published in 1990, the Mifflin-St Jeor formula replaced older BMR equations that routinely overestimated resting metabolism. For men, BMR equals 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5. For women, the constant is −161 instead of +5. Multiplying BMR by an activity multiplier (1.2 for sedentary up to 1.9 for very active) yields TDEE — the number most macro plans are built around.
No formula captures every individual perfectly. Track your weight and gym or run performance for two to three weeks, then adjust calories by 100–150 kcal if progress stalls. The Altus app makes that feedback loop easy — log meals, compare against your targets, and refine as you go.
The Mifflin-St Jeor equation estimates basal metabolic rate (BMR) — the calories your body burns at rest — using age, sex, height, and weight. Research shows it predicts resting energy expenditure more accurately than older formulas like Harris-Benedict for most adults.
BMR is the energy your body needs to stay alive at complete rest. TDEE (total daily energy expenditure) multiplies BMR by an activity factor to account for exercise, walking, and daily movement. Your macro targets are based on TDEE, adjusted for cut, maintain, or bulk goals.
This calculator provides a strong starting point based on population averages. Individual metabolism, muscle mass, sleep, stress, and medical conditions can shift your true needs. Treat the output as a baseline, track progress for two to three weeks, and adjust calories up or down based on scale weight and performance.
This calculator sets protein at roughly 2.6 g per kg of body weight when cutting to preserve muscle, 2.2 g/kg when bulking, and 2.0 g/kg when maintaining. Remaining calories are split between carbs and fat using evidence-based ratios suited to each goal.
Yes. Altus is a free fitness app for iOS and Android with macro tracking, meal logging, and training tools in one place. Enter your targets from this calculator and log meals against them — no subscription required.
Free on iOS and Android — log meals, hit your protein target, and keep training and nutrition in one app.
