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BMR Calculator
Calculate your daily calorie needs
Your Results
Enter your information to calculate your BMR and daily calorie needs
Understanding Basal Metabolic Rate (BMR)
What is BMR?
Basal Metabolic Rate (BMR) is the number of calories your body needs to maintain basic physiological functions at rest. These functions include breathing, circulation, cell production, nutrient processing, and maintaining body temperature. BMR is expressed in calories per day.
BMR vs TDEE
- BMR (Basal Metabolic Rate): Calories burned at complete rest with no activity
- TDEE (Total Daily Energy Expenditure): BMR multiplied by your activity level factor
- Difference: TDEE accounts for physical activity; BMR does not
What Affects BMR?
- Age: BMR decreases approximately 2% per decade after 30
- Gender: Men typically have higher BMR than women
- Height & Weight: Taller and heavier people have higher BMR
- Muscle Mass: Muscle burns more calories than fat at rest
- Genetics: Individual metabolism varies by family history
- Hormones: Thyroid and other hormones affect metabolism
Calorie Goals & Guidelines
Understanding Your Results
- BMR: Your baseline calorie burn at complete rest
- Daily Calories (TDEE): Your total daily energy needs with activity
- Weight Loss Goal: Create 500 calorie deficit for ~0.5 kg loss/week
- Weight Gain Goal: Create 500 calorie surplus for ~0.5 kg gain/week
Calorie Deficit for Weight Loss
- Moderate Deficit (500 cal/day): ~0.5 kg (1 lb) loss per week
- Aggressive Deficit (750 cal/day): ~0.75 kg (1.5 lbs) loss per week
- Very Aggressive (1000 cal/day): ~1 kg (2 lbs) loss per week (not recommended)
Calorie Surplus for Weight Gain
- Moderate Surplus (500 cal/day): ~0.5 kg gain per week (muscle building)
- Large Surplus (1000 cal/day): ~1 kg gain per week (faster muscle growth)
- With strength training: Most gain is muscle; without it, mostly fat
Macronutrient Guidelines
- Protein: 0.8-2.2g per kg of body weight (depending on activity)
- Carbohydrates: 45-65% of total calories
- Fat: 20-35% of total calories
Frequently Asked Questions
Why is my BMR different from online calculators?
Different equations (Harris-Benedict, Katch-McArdle, etc.) produce different results. This calculator uses Mifflin-St Jeor, considered most accurate for healthy adults.
Should I eat my BMR or TDEE calories?
Eat your TDEE calories (BMR × activity level). Eating only BMR calories would be like having no activity level at all, which isn't realistic.
How often does BMR change?
BMR changes gradually with age, weight changes, and muscle gain/loss. Recalculate every few months if your weight or fitness level changes significantly.
Can I eat less than my BMR to lose weight faster?
Not recommended. Eating below BMR can slow metabolism, cause nutrient deficiencies, and lead to muscle loss. A 500 cal deficit is safer and more sustainable.
How accurate is this BMR calculator?
The Mifflin-St Jeor equation is accurate for most healthy adults within 10-20%. However, genetics, hormones, and individual metabolism can cause variations.
Why does my BMR seem high/low?
Individual metabolism varies. Factors like genetics, muscle mass, hormones, and thyroid function affect BMR. If concerned, consult a healthcare professional.
How does exercise increase TDEE?
Exercise burns calories directly. The more intense and frequent your activity, the higher your TDEE multiplier (activity level). Regular exercise increases both calories burned and long-term metabolism.
Should I count water weight in my calculation?
Yes, your total body weight (including water, organs, bones, muscle, and fat) is used to calculate BMR. Don't try to separate water weight for this calculation.
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