BMR / TDEE and Calorie Needs Calculator
Estimate your BMR (Basal Metabolic Rate), TDEE (Total Daily Energy Expenditure), and approximate daily calorie ranges based on age, sex, height, weight, and activity level. For general education only, not medical or nutrition advice.
This calculator is for educational purposes only and does not provide medical, nutrition, or fitness advice. These are rough estimates based on standard equations. For personalized guidance, consult with a registered dietitian or healthcare professional.
Enter Your Information
For adults 18-80 years old
BMR equations use sex-specific formulas. If not provided, an average is used.
Enter your age, sex, height, weight, and activity level to estimate BMR, TDEE, and approximate daily calorie ranges.
Your daily calorie estimate
You plug your numbers into a TDEE calculator and see 2,400 calories flash back. Great, but what does that actually tell you? TDEE stands for Total Daily Energy Expenditure, the rough number of calories your body burns in a 24-hour period when you factor in everything from breathing to walking to that gym session. A common mistake is treating the output as gospel. These formulas estimate; they do not measure. Your real burn can sit 10 to 15 percent higher or lower depending on genetics, muscle mass, hormones, and how honestly you rated your activity level.
The calculator on this page uses the Mifflin-St Jeor equation, which research suggests tends to land closer to measured values than older formulas like Harris-Benedict. You enter age, sex, height, weight, and activity level. It spits out two numbers: BMR (Basal Metabolic Rate), the calories you would burn lying perfectly still all day, and TDEE, which multiplies BMR by an activity factor. Think of BMR as the engine idling and TDEE as the engine running through your actual daily routine.
Use the result as a starting point, not a final answer. If the number says 2,400 and you want to lose weight, you might aim for 1,900 to 2,100 for a few weeks, then adjust based on what the scale and mirror show. If nothing changes, drop a bit more or bump up activity. Calorie math is iterative; the calculator gives you a sensible first guess.
Pick the right activity level
The biggest source of error in any TDEE estimate is the activity multiplier. Most people overestimate how active they are. Hitting the gym three times a week does not automatically make you moderately active if you spend the other 23 hours sitting at a desk or on the couch. Activity level describes your whole day, not just workout time.
Sedentary means you work a desk job, drive to work, and rarely break a sweat outside occasional errands. Lightly active might be a desk job plus two or three short walks or light gym sessions per week. Moderately active fits someone who exercises hard four to five days a week or has a job that keeps them on their feet. Very active applies to daily intense training or a physically demanding job like construction. Extra active is reserved for athletes training multiple hours a day or laborers doing heavy work nonstop.
When in doubt, pick the lower option. You can always add calories back if you find yourself losing weight too fast or feeling drained. Overestimating activity and then eating to match leads to frustration when the scale refuses to budge.
Targets for cut, maintain, or gain
Once you have a TDEE estimate, the next step depends on your goal. For fat loss, you need to eat fewer calories than you burn. A deficit of 300 to 500 calories per day usually translates to losing about half a pound to a pound per week without tanking energy or muscle. Aggressive deficits of 700 or more can speed things up short-term but often backfire through fatigue, muscle loss, and rebound eating.
For maintenance, you eat roughly at TDEE. This is the sweet spot when you want to stay the same weight while potentially improving body composition through training. It also works as a reset after a long diet phase, giving your metabolism a break before pushing into another deficit.
For muscle gain, you eat above TDEE. A surplus of 200 to 400 calories supports growth without piling on excess fat. Bigger surpluses build muscle slightly faster but come with more fat gain that you will need to diet off later. Most lifters find a modest surplus paired with progressive training delivers the best long-term results.
Example: desk job + lifting 3x/week
Common scenario: A 32-year-old man stands 5 feet 10 inches and weighs 185 pounds. He works from home at a computer and lifts weights three mornings a week, each session lasting about an hour. Using the Mifflin-St Jeor formula, his BMR comes out to roughly 1,780 calories. He selects "lightly active" because most of his day is sedentary despite the gym visits. Multiplying BMR by 1.375 gives a TDEE near 2,450 calories. He wants to drop 10 pounds over the next few months, so he targets 1,950 to 2,050 calories per day. After four weeks, the scale shows a 3-pound loss; he keeps the same intake and continues.
Edge case: A 28-year-old woman stands 5 feet 4 inches and weighs 125 pounds. She runs 30 minutes five days a week and walks her dog twice a day. Her BMR calculates to about 1,340 calories. She debates between "moderately active" and "very active." Choosing moderate (1.55 multiplier) gives TDEE around 2,075; choosing very active (1.725) gives TDEE around 2,310. She starts at the moderate estimate, eats 2,100 for two weeks, and notices her weight staying flat. Confident she is not overeating, she bumps intake to 2,200 for maintenance. The conservative start prevented unintentional weight gain.
Plateau checklist and adjustments
Stalls happen. You diet for six weeks, lose steadily, then the scale freezes for ten days. Before slashing calories or doubling cardio, run through a short checklist. First, confirm you are tracking accurately. Eyeballing portions or forgetting that splash of olive oil can add hundreds of hidden calories. Second, check hydration and sodium. A salty meal can mask fat loss with water retention for days. Third, consider sleep and stress. Poor sleep spikes cortisol, which can stall weight loss and bloat you up.
If tracking is tight and lifestyle factors check out, you may need to adjust. Dropping another 100 to 150 calories or adding a 20-minute walk most days can restart progress. Some people prefer a brief diet break—eating at maintenance for a week or two—before resuming the deficit. This can reset hunger hormones and restore energy.
Recalculate TDEE after losing significant weight. A body that once weighed 200 pounds burns fewer calories at 180. If you started with a 500-calorie deficit and lost 15 pounds, that original intake may now be closer to maintenance. Plugging in your new weight keeps the math current.
Sources and references
This calculator uses the Mifflin-St Jeor equation, published in 1990 and widely cited in nutrition research as one of the more accurate predictive formulas for resting metabolic rate in healthy adults. Activity multipliers follow the conventional scale used in dietetics practice, ranging from 1.2 for sedentary individuals to 1.9 for extremely active athletes.
Disclaimer: This calculator is for educational purposes only and does not provide medical or nutrition advice. BMR and TDEE estimates can miss your actual needs by 10 to 15 percent or more. Always consult a registered dietitian or healthcare professional for personalized guidance, especially if you have medical conditions, are pregnant, breastfeeding, or are recovering from an eating disorder.
Frequently Asked Questions
Common questions about BMR, TDEE, calorie needs, and how this calculator works.
What is the difference between BMR and TDEE?
BMR (Basal Metabolic Rate) is the calories your body burns at complete rest—just to keep you alive (breathing, circulating blood, etc.). TDEE (Total Daily Energy Expenditure) is your total daily calorie burn, including BMR plus all your activity throughout the day. TDEE = BMR × activity multiplier. To maintain weight, eat approximately your TDEE. To lose weight, eat less than TDEE; to gain weight, eat more than TDEE.
How accurate are BMR and TDEE calculators?
BMR and TDEE calculators provide rough estimates, typically within 10-15% of your actual needs for most people. However, many factors can affect accuracy: muscle mass (muscle burns more calories than fat), medical conditions, medications, genetics, sleep quality, stress levels, and more. The Mifflin-St Jeor equation used here is considered one of the most accurate, but it's still an estimate. For the most accurate assessment, consider metabolic testing (indirect calorimetry) or work with a registered dietitian who can help you track and adjust based on your actual results.
Can I use these numbers as a strict meal plan?
No. These are educational estimates, not personalized meal plans. The calorie ranges shown are rough guidelines. Your actual needs may be higher or lower based on many factors. Additionally, nutrition isn't just about calories—the quality and balance of macronutrients (protein, carbs, fats), micronutrients (vitamins, minerals), fiber, and meal timing all matter for health. For a personalized meal plan, consult with a registered dietitian who can consider your medical history, food preferences, lifestyle, and goals.
Do these equations work if I am pregnant, breastfeeding, or have a medical condition?
Standard BMR/TDEE equations are not designed for pregnancy, breastfeeding, or many medical conditions. Pregnancy increases calorie needs by 300-500+ calories per day (varies by trimester). Breastfeeding adds 300-500 calories per day. Medical conditions like thyroid disorders, diabetes, heart disease, kidney disease, and others can significantly affect metabolism and require specialized nutrition guidance. If you're pregnant, breastfeeding, or have a medical condition, please consult with a registered dietitian or healthcare provider for personalized guidance.
How often should I recalculate my BMR and TDEE?
Recalculate when your weight changes significantly (10+ pounds), your activity level changes substantially, or you age (though age-related changes are gradual). If you're actively losing or gaining weight, you may want to recalculate every 10-20 pounds, as your BMR will decrease as you lose weight (smaller body = lower BMR) or increase as you gain weight. However, if you're building muscle while losing fat, your BMR might stay relatively stable or even increase slightly.
Why is my calculated BMR lower than I expected?
BMR represents only the calories needed for basic bodily functions at rest—it doesn't include any activity. Many people are surprised that BMR is lower than they thought because they're used to thinking about total daily calorie needs (TDEE). Your TDEE, which includes activity, will be higher. Also, BMR naturally decreases with age and if you have lower muscle mass. If your BMR seems unusually low, double-check your height, weight, and age inputs. If accurate, consider that muscle mass affects BMR—strength training can help increase muscle mass and boost BMR over time.
What if my activity level doesn't fit the categories?
The activity level categories are broad estimates. If you're between categories (e.g., you exercise 4 days/week, which is between 'moderate' and 'active'), you can: (1) Choose the category that best fits your overall lifestyle, (2) Use the lower category for a conservative estimate, or (3) Average the multipliers (e.g., if between moderate 1.55 and active 1.725, use ~1.64). Remember, these are estimates—track your actual food intake and weight changes to see if you need to adjust. Many people find they need to fine-tune based on real-world results.
Is it safe to eat below 1200 calories per day?
For most adults, eating below 1200 calories per day is not recommended without medical supervision. Very low calorie intakes can lead to: nutrient deficiencies, muscle loss (not just fat loss), slowed metabolism, fatigue, dizziness, hair loss, and other health issues. The calculator warns if your gentle weight loss range falls below 1200 kcal/day. If you need to lose weight and your TDEE is already low, consider: (1) Increasing activity to raise your TDEE, (2) Aiming for a smaller deficit (e.g., 200-300 calories instead of 500), or (3) Working with a registered dietitian to create a safe, sustainable plan. Children, teens, and some adults may need higher minimums.
Can I build muscle while losing fat?
Yes, it's possible, especially for beginners, people returning to exercise after a break, or those with higher body fat percentages. This typically requires: (1) A modest calorie deficit (not too aggressive), (2) Adequate protein intake (often 0.8-1.2g per pound of body weight), (3) Strength training to stimulate muscle growth, and (4) Sufficient sleep and recovery. However, it's more challenging than either goal alone. Most people find it easier to focus on one goal at a time: either building muscle in a slight surplus or losing fat in a deficit. A registered dietitian or certified personal trainer can help you design a plan for body recomposition.
Why aren't my results matching what the calculator predicted?
Many factors can cause actual results to differ from calculator estimates: (1) Inaccurate food tracking (underestimating portions is common), (2) Metabolic adaptation (your body may adjust its metabolism in response to diet changes), (3) Water weight fluctuations (can mask fat loss/gain), (4) Changes in muscle mass (affects weight but not necessarily body composition), (5) Medical conditions or medications affecting metabolism, (6) Inaccurate activity level selection, or (7) The calculator is just an estimate. If you're not seeing expected results after 2-4 weeks of consistent tracking, consider: adjusting your calorie target, reassessing your activity level, or consulting with a professional to identify other factors.