BMR + TDEE Calculator

What is Basal Metabolic Rate (BMR)? How to Calculate & Boost It

Your Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to maintain vital functions like breathing, circulation, and cell production. Understanding your BMR helps you estimate daily calorie needs for weight loss, maintenance, or muscle gain.

Why BMR Matters

• 70% of your daily calorie burn comes from BMR (keeping organs functioning).

• Physical activity contributes ~20%, and digestion (thermogenesis) makes up ~10%.

• Knowing your BMR helps tailor diet and exercise plans for better results.

How to Calculate BMR

The most accurate equations are:

1. Mifflin-St Jeor Equation (Most Accurate for Most People)

For Men:
BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age) + 5

For Women:
BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age) – 161

2. Revised Harris-Benedict Equation (Older but Still Used)

For Men:
BMR = (13.397 × weight in kg) + (4.799 × height in cm) – (5.677 × age) + 88.362

For Women:
BMR = (9.247 × weight in kg) + (3.098 × height in cm) – (4.330 × age) + 447.593

3. Katch-McArdle Formula (Best for Lean Individuals)

If you know your body fat percentage:
BMR = 370 + (21.6 × lean body mass in kg)
(Lean body mass = Total weight – Fat weight)

👉 Tip: Use an online BMR calculator for quick estimates!

Factors That Affect BMR

1. Muscle Mass

• Muscle burns more calories at rest than fat.

• Strength training increases BMR over time.

2. Age

• BMR declines with age due to muscle loss and hormonal changes.

3. Genetics

• Some people naturally have a faster or slower metabolism.

4. Diet & Eating Patterns

• Eating small, frequent meals can slightly increase BMR.

• Starvation or extreme calorie restriction lowers BMR.

5. Hormones & Health Conditions

• Thyroid issues, pregnancy, and menopause impact BMR.

6. Environmental Temperature

• Cold weather increases BMR (body works harder to stay warm).

How to Boost Your BMR Naturally

✅ Build muscle with resistance training (weightlifting, bodyweight exercises).
✅ Eat enough protein (thermic effect of food increases calorie burn).
✅ Stay active (NEAT—non-exercise activity—helps maintain metabolism).
✅ Get enough sleep (poor sleep slows metabolism).
✅ Drink caffeine or green tea (temporarily increases metabolic rate).

BMR vs. RMR: What’s the Difference?

• BMR is measured under strict lab conditions (full rest, no digestion).

• RMR (Resting Metabolic Rate) is a more practical estimate (measured under relaxed conditions).

• For most people, the terms are used interchangeably.

Limitations of BMR Calculations

• Even the best formulas have a ~26% margin of error due to individual differences.

• The most accurate method is indirect calorimetry (available at some clinics).

• Tracking food intake, exercise, and progress is more reliable than BMR alone.

Final Thoughts

Your BMR is a key factor in weight management, but it’s just an estimate. Combine BMR calculations with real-world tracking—adjust your diet and exercise based on results for the best outcomes.

💡 Want a personalized plan? Try our free BMR calculator and get tailored nutrition and fitness training from our trainers!