Calculate TDEE, BMR, and calorie goals for your weight goals
Basal Metabolic Rate (BMR) is the number of calories your body needs to accomplish its most basic (basal) life-sustaining functions, such as breathing, circulation, nutrient processing, and cell production.
Note: These are estimates based on averages. Individual calorie needs vary based on genetics, metabolism, and other factors. Consult a healthcare professional for personalized advice.
Your body burns calories 24/7, even while sleeping. Understanding the difference between BMR and TDEE is crucial for effective weight management.
Your BMR represents the calories needed for essential functions: breathing, circulating blood, producing cells, and maintaining body temperature. This accounts for 60-75% of your total daily energy expenditure. Interestingly, your brain alone uses about 20% of your BMR - roughly 320 calories daily for the average adult.
TDEE = BMR + Activity Calories + Thermic Effect of Food (TEF). TEF is the energy required to digest, absorb, and process nutrients - about 10% of calories consumed. Protein has the highest TEF (20-30%), meaning you burn more calories digesting protein than carbs (5-10%) or fats (0-3%).
Different equations exist because no single formula perfectly predicts everyone's metabolism. Here's how they differ:
Mifflin-St Jeor ⭐
Most accurate for general population (±10% error rate). Developed in 1990 using data from 498 subjects. Best for: Most people, standard body composition.
Harris-Benedict (Revised)
Original 1919 formula, revised 1984. Tends to overestimate by 5% due to historical differences in body composition. Best for: Historical comparison only.
Katch-McArdle
Uses lean body mass instead of total weight. Most accurate if you know your body fat percentage (±5% error). Best for: Athletes, bodybuilders, very lean individuals.
These equations don't account for: genetics (metabolism varies 20-30% between individuals), hormonal conditions (thyroid disorders, PCOS), medications, sleep quality, stress levels, or previous dieting history. Use these as starting points, then adjust based on real-world results over 2-3 weeks.
You've probably heard that 3,500 calories equals one pound. While this is the traditional teaching, modern science shows it's more complex:
The 3,500 calorie rule assumes your metabolism stays constant, but it doesn't. As you lose weight, your BMR decreases (fewer cells to maintain). A 200-pound person burns more calories existing than a 150-pound person. This is why weight loss slows over time - you need progressively fewer calories.
Additionally, your body adapts to calorie restriction through 'metabolic adaptation' - your metabolism can slow by 10-25% beyond what's expected from weight loss alone. This is why aggressive dieting often backfires. The Minnesota Starvation Experiment (1944) showed participants' metabolisms dropped 40% on semi-starvation diets.
Your body has a 'set point' - a weight range it tries to defend. When you eat less, your body fights back by: increasing hunger hormones (ghrelin), decreasing satiety hormones (leptin), reducing fidgeting and unconscious movement (NEAT), and lowering body temperature slightly. This is why 'eat less, move more' is technically correct but practically insufficient advice.
Protein increases satiety, preserves muscle during weight loss, and has the highest thermic effect. Aim for 1.6-2.2g per kg of body weight during a deficit. This means a 75kg person should target 120-165g daily. Example: 6oz chicken breast (54g), 1 cup Greek yogurt (20g), 2 eggs (12g), protein shake (25g) = 111g.
Cardio burns calories during exercise. Weight training burns calories and builds muscle that burns calories 24/7. Every pound of muscle burns 6-10 calories daily at rest vs 2-3 for fat. A 10-pound muscle gain could increase BMR by 60-100 calories daily. Train each muscle group 2x per week minimum.
One night of poor sleep (4-5 hours) can decrease insulin sensitivity by 25%, increase ghrelin by 28%, and decrease leptin by 18%. Chronic sleep deprivation is associated with 55% higher obesity risk. Similarly, chronic stress elevates cortisol, which promotes fat storage, especially visceral (belly) fat. Aim for 7-9 hours nightly.
Total calories matter most, but timing can help adherence. Three approaches work: (1) Intermittent fasting (16:8) - may reduce total calorie intake by limiting eating window, (2) 3-4 regular meals - good for blood sugar stability, (3) 5-6 small meals - may help those with constant hunger. Choose what you can sustain. Evening eating doesn't make you fatter if calories are equal.
A 200-calorie snack can leave you satisfied for hours or hungry in 30 minutes. The difference? Nutrient density and how your body processes different foods.
Research suggests humans have a dominant appetite for protein. If protein intake is low, you'll unconsciously eat more total calories to meet protein needs. This is why high-protein diets are effective - 25-30% protein makes it easier to maintain a deficit without conscious restriction. Studies show people eating 30% protein naturally consume 400-500 fewer calories daily vs 10% protein diets.
Fiber slows gastric emptying (food leaves stomach slower), reduces ghrelin (hunger hormone), and feeds beneficial gut bacteria. Target 25-35g daily. High-fiber foods include: berries (8g/cup), beans (15g/cup), broccoli (5g/cup), oats (4g per serving). Interestingly, soluble fiber (oats, beans) may reduce calorie absorption by 4-7% through binding with fats.
Food manufacturers engineer products to maximize consumption by combining fat + sugar + salt in precise ratios that override satiety signals. Common examples: pizza, ice cream, chips, cookies. These foods have weak satiety responses - you can eat 1,000 calories and still feel hungry. Strategy: Make these occasional treats, not staples. Focus on single-ingredient foods that are hard to overeat (try bingeing on grilled chicken or broccoli).
Foods high in water content have low calorie density but high satiety. 500 calories of grapes (7 cups) vs 500 calories of raisins (1.5 cups) - same calories, vastly different satiety. Volume matters. Prioritize: soups, fruits, vegetables, lean proteins. Minimize: dried fruits, nuts (healthy but calorie-dense), oils, processed snacks.
After 2-3 weeks in a deficit, leptin drops significantly, hunger increases, and metabolism slows. Strategy: Every 7-14 days, eat at maintenance calories (focusing on carbs) for 1-2 days. This partially restores leptin, improves training performance, and provides a psychological break. Or, after 8-12 weeks dieting, take a full 2-week diet break at maintenance. Research shows this can preserve muscle and metabolism better than continuous dieting.
Non-Exercise Activity Thermogenesis (NEAT) includes all movement outside formal exercise - fidgeting, walking, typing, standing. NEAT can vary by 2,000 calories daily between individuals. When you diet, NEAT unconsciously drops (you sit more, fidget less, take elevators vs stairs). Combat this: track daily steps (aim for 8,000-10,000), use a standing desk, park farther away, take walking meetings. These 'mini-movements' accumulate significantly.
Match fueling to activity. Training days: eat maintenance or slight surplus with higher carbs (fuels performance, aids recovery). Rest days: moderate deficit with lower carbs, higher protein/fats (promotes fat loss, preserves muscle). Example for 2,500 TDEE: Training days 2,500-2,700 (250g carbs), Rest days 2,000-2,200 (100g carbs). Weekly deficit: 1,500 calories, but with performance benefits.
After reaching your goal, don't immediately jump to maintenance calories. Gradually increase calories by 50-100 weekly (focus on carbs/fats). This allows metabolism to adapt upward, minimizes fat regain, and helps identify your new maintenance. Expect 4-8 weeks to reverse from aggressive deficit to full maintenance. Yes, this requires patience, but prevents the classic diet-binge-regain cycle.
The answer depends on dozens of factors, and the calculator gives you a starting point - not the final answer. Here's what really influences your calorie needs:
Two people with identical stats (age, weight, height, activity) can have metabolisms that differ by 20-30%. This is due to genetics, thyroid function, gut microbiome composition, brown adipose tissue levels, and previous dieting history. The calculator gives you an average - you need to adjust based on real-world results over 2-3 weeks.
Metabolism drops about 1-2% per decade after age 30, primarily due to muscle loss, not aging itself. A 50-year-old who maintains muscle mass through resistance training may have a higher BMR than a sedentary 30-year-old. The solution isn't accepting slower metabolism - it's preserving muscle through strength training and adequate protein.
Men typically have 10-15% higher BMR than women of the same weight due to higher muscle mass and lower body fat percentage. However, women's calorie needs fluctuate throughout the menstrual cycle - TDEE can increase 100-300 calories during the luteal phase (week before period). This is why women shouldn't panic over weekly weight fluctuations.
If you work a desk job, you're sedentary - even if you work out 1 hour daily. That's 1 hour active, 23 hours sedentary. 'Lightly active' means being on your feet most of the day (teacher, nurse, retail worker). When in doubt, choose one level lower than you think. It's easier to add calories later than deal with no progress.
Women: 1,200 calories minimum, Men: 1,500 calories minimum. Below these thresholds, it becomes nearly impossible to meet micronutrient needs without supplementation. Very low calorie diets (VLCDs) also cause: muscle loss (up to 25% of weight lost), metabolic slowdown, hormonal disruption (low testosterone, irregular periods), decreased bone density, and increased risk of gallstones. Aggressive deficits should only be done under medical supervision.
Athletes & high activity: May need 3,000-5,000+ calories. Pregnant/nursing: Add 300-500 calories. Post-menopausal women: May need 200-300 fewer calories due to hormonal changes. Thyroid conditions: Hypothyroidism can lower BMR by 20-40%. PCOS: Often have 5-10% lower BMR. Medications: Some (antidepressants, antipsychotics, corticosteroids) can affect metabolism by 10-20%.
Bites, Licks, and Tastes add up. One tablespoon of olive oil is 120 calories. Coffee creamer, salad dressing, mayo, BBQ sauce - these 'small' additions can add 300-500 hidden calories daily. Fix: measure oils with a tablespoon, track everything that enters your mouth for 1 week to identify blind spots.
Fitness trackers overestimate calorie burn by 20-40%. A '500 calorie' workout is often 300-350 calories. If you eat back all estimated calories, you've eliminated your deficit. Fix: don't eat back exercise calories, or only eat back 50% if doing intense training (2+ hours daily).
Perfect diet Monday-Friday (1,800 cal deficit), then splurge Saturday-Sunday (+3,000 cal surplus). Net weekly result: +1,200 calories or 0.3 pound gained. Your body doesn't reset on Mondays. Fix: allow 10-20% more calories on weekends (2,000 vs 1,800), plan social events, practice moderation not restriction.
Alcohol provides 7 calories per gram (vs 4 for protein/carbs, 9 for fat). A night of drinking can easily add 800-1,500 calories. Plus, alcohol reduces fat oxidation (your body prioritizes burning alcohol over fat), increases appetite, and decreases inhibition around food. Fix: limit to 1-2 drinks, choose lower-calorie options (vodka soda vs beer/cocktails), eat before drinking to reduce appetite spike.