BMR & TDEE Calculator
Calculate your Basal Metabolic Rate and Total Daily Energy Expenditure for weight management.
Basal Metabolic Rate (BMR)
1,628
kcal/day at complete rest
TDEE (with selected activity)
2,523
kcal/day to maintain weight
Activity level
Calorie targets from BMR
Weight Loss
2,023 kcal
-500/day deficit
Maintenance
2,523 kcal
Muscle Gain
2,823 kcal
+300/day surplus
About the BMR & TDEE Calculator
Your Basal Metabolic Rate (BMR) is the number of calories your body burns each day just to stay alive - without any movement, exercise, or digestion. It accounts for 60-75% of your total calorie burn. Without knowing your BMR, calorie targets are guesswork. With it, you can set precise deficits for fat loss, maintenance for body recomposition, or surpluses for muscle gain. The Mifflin-St Jeor equation (1990) is the gold standard recommended by the American Dietetic Association for accuracy in modern populations.
Mifflin-St Jeor BMR Formula
Male: BMR = 10W + 6.25H - 5A + 5 | Female: BMR = 10W + 6.25H - 5A - 161
W = Weight in kg | H = Height in cm | A = Age in years | TDEE = BMR x Activity Factor (1.2 to 1.9)
Worked Example
28-year-old male, 70 kg, 170 cm, moderately active (3-5 days/week exercise)
BMR: 1,695 kcal/day | TDEE: 2,627 kcal/day | Weight loss target: 2,127 kcal/day (-500) | Muscle gain: 2,927 kcal/day (+300)
Tips & Insights
- 1
Never eat below your BMR. It triggers muscle loss and metabolic adaptation - your body will slow its burn rate to match intake.
- 2
A 500 calorie daily deficit = 1 kg of fat loss in about 2 weeks (3,500-7,700 cal per kg of fat). This is a safe, sustainable rate.
- 3
Muscle burns 3x more calories at rest than fat. Adding 5 kg of muscle raises BMR by 75-100 kcal/day permanently.
- 4
BMR decreases with age by about 1-2% per decade due to muscle loss (sarcopenia). Resistance training is the most effective counter.
- 5
Protein has a 25-30% thermic effect - your body burns 25 cal to process 100 cal of protein vs only 5 cal for carbs/fat. High protein diets slightly boost TDEE.
- 6
The activity factor is often overestimated. Most office workers who gym 3 days/week are 'lightly active' (1.375), not 'moderately active' (1.55).
Why this matters for you
Without a TDEE calculation, people either undereat (crash diet, muscle loss, rebound) or overeat while thinking they are being healthy. A 200 calorie/day surplus above TDEE - barely a glass of juice - can add 8 kg per year. A 500 calorie deficit - roughly one meal skipped - can remove 1 kg of fat per fortnight. The BMR/TDEE framework transforms nutrition from vague advice into an engineering problem with measurable inputs and predictable outputs.
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