Calculate your Basal Metabolic Rate to discover how many calories your body burns at complete rest.
Calculate your Basal Metabolic Rate to discover how many calories your body burns at complete rest.
💡 This tool provides estimates as a guide. Individual results may vary.
Your BMR is the foundation for every nutrition and weight management decision you'll make. It tells you the minimum calories your body needs just to stay alive—powering your heart, lungs, brain, and every cell. For busy professionals and parents juggling work deadlines, family responsibilities, and personal health goals, knowing this number removes the guesswork from eating.
Instead of bouncing between restrictive diets that leave you exhausted or overeating and wondering why the scale won't budge, BMR gives you a concrete starting point. Once you know this number, you can set realistic calorie targets using our Maintenance Calorie Calculator, then dial in your nutrition with our Macro Calculator and Protein Calculator. Think of it as your metabolism's baseline—everything else builds from here.
Your Basal Metabolic Rate (BMR) is the number of calories your body needs to perform basic life-sustaining functions at complete rest. This includes breathing, circulating blood, regulating body temperature, cell production, nutrient processing, and brain function.
BMR represents the minimum energy your body requires just to stay alive if you did absolutely nothing all day—no walking, no eating, no thinking beyond basic survival. It typically accounts for 60-75% of your total daily calorie expenditure.
Think of BMR as your body's "idle speed." Just like a car engine burns fuel even when parked and running, your body constantly burns calories to keep your organs functioning and systems running smoothly.
Our calculator uses the Mifflin-St Jeor equation, which research shows is the most accurate formula for estimating BMR. The formulas are:
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
For example, a 35-year-old woman who weighs 70 kg and is 165 cm tall:
BMR = (10 × 70) + (6.25 × 165) - (5 × 35) - 161 = 700 + 1,031 - 175 - 161 = 1,395 calories/day
Understanding the difference between BMR and TDEE is crucial for setting the right calorie targets:
BMR (Basal Metabolic Rate)
Calories burned at complete rest—lying in bed all day without moving. This is your body's minimum energy requirement.
TDEE (Total Daily Energy Expenditure)
Calories burned throughout your entire day—including all activity, exercise, digestion, and daily movement. This is your actual daily calorie needs.
To calculate TDEE, multiply your BMR by an activity multiplier:
Most people should eat at their TDEE to maintain weight, not their BMR. Eating only BMR calories would be too low and could slow your metabolism.
Several factors influence how many calories your body burns at rest:
While you can't change your age or genetics, you can influence your BMR through strength training, adequate protein intake, and avoiding extreme calorie restriction.
Your BMR is the foundation for setting calorie targets, but you need to factor in activity:
To Maintain Weight:
Eat at your TDEE (BMR × activity multiplier). This keeps your weight stable while supporting your activity level.
To Lose Weight:
Eat 300-500 calories below TDEE (not below BMR). Aim for 0.5-1% body weight loss per week for sustainable fat loss.
To Gain Muscle:
Eat 200-300 calories above TDEE while following a strength training program. This supports muscle growth without excessive fat gain.
Important: Never eat significantly below your BMR for extended periods. Your body needs at least BMR calories to maintain organ function, hormone production, and metabolic health. Extreme restriction can cause:
How accurate is the BMR calculator?
The Mifflin-St Jeor equation is accurate within ±10% for most people. Individual variation exists due to genetics, muscle mass, and metabolic adaptations. Use the result as a starting point and adjust based on your real-world results over 2-4 weeks.
Can I increase my BMR?
Yes, but only modestly. Building muscle through strength training is the most effective way—each pound of muscle burns about 6 calories per day at rest. While that sounds small, gaining 10 pounds of muscle adds 60 calories daily, or 21,900 calories yearly (equivalent to 6 pounds of fat).
Should I eat at my BMR to lose weight?
No. You should eat at your TDEE minus 300-500 calories, which is almost always higher than your BMR. Eating at BMR ignores your daily activity and can be too restrictive, leading to muscle loss and metabolic slowdown.
Why is my BMR lower than my friend's?
BMR varies based on age, sex, size, and muscle mass. Larger, younger, male, and more muscular individuals have higher BMRs. A 6'2" athletic 25-year-old man might have a BMR of 2,000+ calories, while a 5'2" sedentary 50-year-old woman might have a BMR of 1,200 calories.
Does BMR decrease with age?
Yes, by about 1-2% per decade after age 20. This happens primarily because people lose muscle mass as they age (sarcopenia). However, you can maintain or even increase your BMR through consistent strength training and adequate protein intake.
Will eating more protein increase my BMR?
Protein has a higher thermic effect (calories burned during digestion) than carbs or fats, and it helps preserve muscle during weight loss. While protein won't dramatically raise BMR, it does support muscle maintenance, which indirectly protects your metabolism.
What's "metabolic damage" and can it affect BMR?
"Metabolic damage" isn't technically accurate, but metabolic adaptation is real. When you diet for extended periods, especially with very low calories, your body becomes more efficient (burns fewer calories). This can lower BMR by 10-15%. The solution is diet breaks, reverse dieting, and prioritizing muscle retention.
How does BMR relate to "fast" or "slow" metabolism?
When people say they have a "fast metabolism," they usually mean a higher TDEE (not necessarily BMR). While BMR does vary, most of the difference comes from daily activity (NEAT—Non-Exercise Activity Thermogenesis). Active people burn significantly more calories than sedentary people, even if their BMRs are similar.
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