BMR Calculator to Lose Weight

This BMR calculator gives you a personalized weight loss plan based on your age, height, weight, and gender. Get your BMI, daily calorie needs, meal guide, and workout plan—all in one place.

Have you ever felt like you’re doing everything right—eating less, moving more—but the scale just won’t budge? The secret may lie in your BMR, or Basal Metabolic Rate. This is the number of calories your body burns just to stay alive—even when you're resting. Understanding BMR can be the key to unlocking more effective, sustainable weight loss.

What Is BMR? (Basal Metabolic Rate Explained Simply)

Basal Metabolic Rate (BMR) is the number of calories your body burns at rest to maintain vital functions like breathing, circulation, and cell production. According to Cleveland Clinic. (2023) [1], BMR supports all your vital organs—including the heart, lungs, brain, and kidneys—even while you're asleep.

Think of your body like a car. Even if you're not driving it, it still needs fuel just to stay on. That fuel is your BMR. It powers basic functions like breathing, circulating blood, keeping your organs working, and maintaining your body temperature. You burn calories doing absolutely nothing—thanks to your BMR.

BMR is different from TDEE (Total Daily Energy Expenditure), which includes all the calories you burn from eating, moving, and exercising.

Why BMR Matters for Fat Loss

BMR matters for fat loss because it determines how many calories your body burns at rest, which accounts for the majority of your daily energy expenditure. If you create a calorie deficit without considering your BMR, you risk slowing your metabolism and losing muscle instead of fat.

Your BMR makes up about 70% of the calories you burn each day. That means your metabolism—not your workouts—is doing most of the work.

If you eat fewer calories than your BMR, your body might panic and slow your metabolism down even more to conserve energy—a survival response known as adaptive thermogenesis [2], as explained by Harvard Health Publishing. This is why extreme dieting often backfires.

Knowing your BMR helps you plan a healthy calorie deficit: enough to lose fat, but not so much that your body fights back.

How to Calculate BMR

You can calculate your BMR using scientifically validated formulas, with the Mifflin-St Jeor Equation being the most widely recommended. This formula takes into account your weight, height, age, and sex to estimate how many calories your body uses at rest. Depending on your preference, you can use metric or imperial units—and for more advanced cases, other formulas like Harris-Benedict or Katch-McArdle may offer tailored insights.

Most accurate: Mifflin-St Jeor Equation

Among all BMR equations, the Mifflin-St Jeor Equation [3] is the most accurate for healthy adults, as validated in a 1990 clinical study published in the American Journal of Clinical Nutrition.

Metric Units

• For men: 10 x weight (kg) + 6.25 x height (cm) - 5 x age (years) + 5
• For women: 10 x weight (kg) + 6.25 x height (cm) - 5 x age (years) - 161

Imperial Units

• For men: 66 + (6.23 × weight in lbs) + (12.7 × height in inches) - (6.8 × age)
• For women: 655 + (4.35 × weight in lbs) + (4.7 × height in inches) - (4.7 × age)

Example: A 35-year-old woman, 160 cm tall, weighing 60 kg:
10x60 + 6.25x160 - 5x35 - 161 = 600 + 1000 - 175 - 161 = 1,264 calories/day

Revised Harris-Benedict Equation

The Revised Harris-Benedict Equation [4] is similar in structure to the Mifflin-St Jeor formula but was developed earlier and may be slightly less accurate for modern populations. It still provides a reliable estimate of BMR, especially when detailed body composition data is unavailable.

Metric

• For men: 88.362 + (13.397 × weight in kg) + (4.799 × height in cm) - (5.677 × age)
• For women: 447.593 + (9.247 × weight in kg) + (3.098 × height in cm) - (4.330 × age)

Imperial

• For men: 66.5 + (6.23 × weight in lbs) + (12.7 × height in inches) - (6.8 × age)
• For women: 655.1 + (4.35 × weight in lbs) + (4.7 × height in inches) - (4.7 × age)

Katch-McArdle Formula

The Katch-McArdle Formula [5] is most accurate when you know your body fat percentage, as it calculates BMR based on lean body mass rather than total body weight.

• Metric Formula: 370 + (21.6 × lean body mass in kg)
• Imperial Formula: 370 + (9.8 × lean body mass in lbs)

Oxford Formula

The Oxford Formula [6] was developed using data from a large and diverse population sample, making it useful for estimating BMR across various ethnicities, age groups, and body types.

Metric Formulas

• Men:

  • Ages 18 to 30: BMR = 16.0 × weight (kg) + 545
  • Ages 31 to 60: BMR = 14.2 × weight (kg) + 593
  • Age 61 and older: BMR = 13.5 × weight (kg) + 514

• Women:

  • Ages 18 to 30: BMR = 13.1 × weight (kg) + 558
  • Ages 31 to 60: BMR = 9.74 × weight (kg) + 694
  • Age 61 and older: BMR = 10.1 × weight (kg) + 569

Imperial Formulas

• Convert weight in pounds to kilograms first: weight (lbs) ÷ 2.2, then apply the metric formula above for your age and gender group.

How to Use Your BMR to Create a Fat Loss Calorie Deficit

To use your BMR for fat loss, start by calculating how many calories your body burns at rest, then adjust your daily intake to create a moderate calorie deficit. Multiply your BMR by an activity factor to estimate your Total Daily Energy Expenditure (TDEE), and subtract 300–500 calories per day, which is recommend by CDC [7], to lose fat safely without slowing your metabolism.

1. Calculate BMR

2. Multiply by an activity factor to get TDEE (Total Daily Energy Expenditure):

   • Sedentary (little or no exercise): x1.2
   • Light activity: x1.375
   • Moderate: x1.55
   • Active: x1.725
   • Very active: x1.9

3. Create a safe calorie deficit of 300–500 calories/day

This method supports fat loss without crashing your metabolism.

How to Build a Diet Plan Based on Your BMR

Your BMR is the foundation of any effective diet plan—it tells you how many calories your body needs just to function at rest. According to Colorado State University Extension [8], understanding your BMR helps you estimate how many calories you should consume each day based on your activity level and personal health goals.

Once you have this baseline, you can adjust your intake to support fat loss, maintenance, or muscle gain.

🥗 Steps to Create a BMR-Based Diet Plan:

1. Start with your BMR – This is your resting calorie requirement.

2. Add activity level – Multiply your BMR by your activity factor to get your TDEE (Total Daily Energy Expenditure).

3. Set your goal:

   • For fat loss: Eat 300–500 calories below your TDEE.
   • For maintenance: Match your intake to your TDEE.
   • For muscle gain: Add 200–300 calories above TDEE.

4. Balance your macros:

   • Protein: Aim for 1.2–2.0 g per kg of body weight to support muscle.
   • Carbs and fats: Fill in the rest based on preference and energy needs.

5. Stay flexible – Adjust your intake weekly based on progress, hunger, and energy levels.

⚠️ Avoid This:

• Don’t eat below your BMR—this can lead to muscle loss and a slower metabolism.

How to Increase BMR Naturally and Safely

According to a 2024 review published in The American Journal of Medicine [9], your Basal Metabolic Rate (BMR) is determined by a combination of fixed factors—such as age, sex, and genetics—and modifiable factors including lean muscle mass, physical activity, and dietary intake.

Fixed factors:

• Age – BMR naturally slows as you get older
• Gender – Men usually have higher BMRs due to more muscle mass
• Genetics – Some people are just born with a faster or slower metabolism

Changeable factors:

• Muscle mass – More muscle = higher BMR
• Health – Thyroid problems, illnesses, or even stress can affect BMR
• Food habits – Long-term under-eating can lower BMR

You can’t change your age or genetics—but you can increase your Basal Metabolic Rate (BMR) naturally by adjusting your daily habits. The most effective and sustainable ways include building muscle, staying active, eating enough calories, and prioritizing sleep. These strategies support your metabolism and help your body burn more calories, even at rest.

Here’s how to boost your BMR safely:

• Build muscle: Strength training increases lean mass, which raises your resting calorie burn.
• Eat enough: Severely restricting calories slows your metabolism—fuel your body properly.
• Stay active: Daily movement, even walking, helps maintain a higher metabolic rate.
• Sleep well: Aim for 7–9 hours per night; poor sleep disrupts metabolic hormones.

⚠️ While stimulants like caffeine may temporarily raise your BMR, they are not a long-term solution and can stress your body over time.

BMR Mistakes to Avoid—and How to Maintain a Healthy Metabolism While Losing Weight

Many people unknowingly sabotage their metabolism during weight loss by believing common myths about Basal Metabolic Rate (BMR). Understanding what not to do is just as important as knowing what works. Here are key misconceptions to avoid—and science-backed strategies to protect your BMR:

❌ Common BMR Myths:

• “A high BMR means I’ll lose weight easily” – Not if you’re still eating more than you burn. BMR is only part of the equation.
• “Starving helps you lose fat faster” – Severely cutting calories slows your metabolism and leads to muscle loss.
• “Only cardio burns calories” – Strength training is essential for maintaining muscle and keeping BMR elevated.

✅ Best Practices to Maintain BMR During Fat Loss:

• Eat enough protein – Supports muscle retention during a calorie deficit.
• Avoid undereating – Stay above your BMR to prevent metabolic slowdown.
• Incorporate weight training – Builds lean mass, which burns more at rest.
• Prioritize sleep – Aim for 7–9 hours to regulate metabolic hormones.
• Track your progress – Monitor intake, activity, and weight trends to adjust as needed.

Conclusion: Make BMR Work With You, Not Against You

Your BMR is the foundation of your metabolism. Use it to plan smarter, not harder. Instead of chasing quick fixes, build a lifestyle that fuels your body, protects your metabolism, and gets results that actually last.

Ready to start? Calculate your BMR and create a fat-loss plan that’s built to succeed.

Reference

1. Cleveland Clinic. (2023). Basal Metabolic Rate (BMR): What It Is and How to Use It. Cleveland Clinic.
2. Harvard Health Publishing. (2021). The truth about metabolism. Harvard Medical School.
3. Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition. 1990; 51(2): 241–247.
4. Roza AM, Shizgal HM. (1984). The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass. The American Journal of Clinical Nutrition, 40(1), 168–182.
5. Katch VL, McArdle WD, Katch FI. (2011). Essentials of Exercise Physiology (4th ed.). Philadelphia: Lippincott Williams & Wilkins.
6. Henry C. J. (2005). Basal metabolic rate studies in humans: measurement and development of new equations. Public health nutrition, 8(7A), 1133–1152.
7. Centers for Disease Control and Prevention. (n.d.). Burn more calories than you take in (Participant Module 7). National Diabetes Prevention Program. U.S. Department of Health and Human Services.
8. Colorado State University Extension. (2020). Basal Metabolic Rate & Your Eating Plan.
9. Cohen, R. V., Colberg, S. R., Kirwan, J. P., Petersen, K. F., Taylor, R., & Klein, S. (2024). Metabolism: A primer. The American Journal of Medicine, 137(4), 361–372.