How to use this calculator
- 1
Enter your stats
Input age, sex, height, and weight in your preferred units (imperial or metric).
- 2
Pick your activity level
Choose from sedentary (1.2) to extreme (1.9) based on weekly exercise frequency and step count.
- 3
Select your goal
Maintain, cut (–10 to –25%), or bulk (+10 to +20%) — the calculator adjusts target calories automatically.
- 4
Read your result
See BMR from three formulas, TDEE, daily calorie target, macro split (protein / carbs / fat), and projected weekly weight change.
What this calculator gives you
- Three peer-reviewed BMR formulas (Mifflin-St Jeor, Harris-Benedict, Katch-McArdle)
- Optional body-fat input for the most accurate Katch-McArdle result
- Automatic macro split tuned to your goal
- BMI, ideal weight, and FFMI estimates
- Imperial and metric, with instant unit toggle
- No signup, no tracking, all calculations run in your browser
Formulas used
Mifflin-St Jeor (1990)
Men: BMR = 10×kg + 6.25×cm − 5×age + 5 Women: BMR = 10×kg + 6.25×cm − 5×age − 161
Best for: General population — most accurate within ±10%
Harris-Benedict (revised 1984)
Men: BMR = 88.362 + 13.397×kg + 4.799×cm − 5.677×age Women: BMR = 447.593 + 9.247×kg + 3.098×cm − 4.330×age
Best for: Comparison reference; tends to overestimate sedentary BMR
Katch-McArdle
BMR = 370 + 21.6 × LBM(kg)
Best for: Anyone with a known body-fat % — most accurate for lean and athletic populations
Frequently asked questions
What is TDEE?+
TDEE (Total Daily Energy Expenditure) is the total calories your body burns in 24 hours, including basal metabolic rate, exercise, daily movement, and digestion.
Which BMR formula does this calculator use?+
It calculates all three (Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle when body fat is provided) and recommends the most accurate one for your inputs.
How accurate is this TDEE calculator?+
Within roughly ±10% for most adults. Individual variation in NEAT, gut microbiome, and adaptive thermogenesis can shift true TDEE another 5–15%. Use the result as a starting point and adjust based on real-world tracking over 2–3 weeks.
Should I eat back exercise calories?+
No — exercise is already included in your activity multiplier. Only eat back calories on days with unusually high activity beyond your usual training.
Is this calculator free?+
Yes — completely free, no signup required. All calculations run in your browser; no data is collected or stored.
Want the full guide?
The complete article goes deeper into the science, with charts, comparisons, and practical examples.
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