Calorie Calculator: Complete TDEE, BMR & Macro Guide
How to calculate daily calories for weight loss or gain. Mifflin-St Jeor, Harris-Benedict, Katch-McArdle. Trusted by trainers. No sign-up—all calculations run locally.
What This Calculator Does & Who It's For
Calculator Purpose & Ideal Users
- Primary Use Cases:Weight loss planning: Calculate sustainable deficit targets (not arbitrary low numbers). Muscle building: Determine surplus calories for lean mass gains. Maintenance tracking: Establish baseline for intuitive eating or reverse dieting. Macro optimization: Get protein/carb/fat targets for specific diet strategies. Plateau troubleshooting: Use zig-zag cycling to break through stalls.
- Ideal User Profiles:Adults 18-65: Formulas validated for this age range. Those starting a diet: Baseline data prevents guesswork and crash dieting. Fitness enthusiasts: Macro calculations support training goals. Anyone tracking food: Provides calorie/macro targets for apps like MyFitnessPal. People recovering from crash diets: Reverse dieting calculations help restore metabolism.
- Who Should Use Caution:Adolescents/elderly: Formulas less validated; use as rough estimates. Pregnant/nursing: Add 300-500 cal/day beyond calculated TDEE. Those with eating disorders: Calculator should not justify extreme restriction—seek professional guidance. Post-bariatric surgery: Metabolic needs change significantly; clinical measurement recommended.
- When NOT to Use This Calculator:Do not use as primary guidance if you have: diagnosed metabolic disorders (thyroid, PCOS, diabetes without medical team input), active eating disorder or history of disordered eating, BMI under 18.5 (underweight), or are under 18 or over 70. In these cases, work with healthcare providers who can measure actual metabolic rate and account for medical factors.
- Scope & Limits:Uses Mifflin-St Jeor, Harris-Benedict, or Katch-McArdle for BMR; TDEE = BMR × activity multiplier. Estimates only; individual variation ±10–15%. All calculations run locally; no data stored. Consult a healthcare provider or dietitian for personalized nutrition.
This calorie calculator estimates your Total Daily Energy Expenditure (TDEE)—the actual calories you burn daily including all activity—then provides goal-specific targets for weight loss, maintenance, or muscle gain with customizable macronutrient splits.
Understanding Each Input & Why It Matters
Input Field Reference Guide
- Age (18-100 years):BMR decreases ~2% per decade due to muscle loss and hormonal changes. The formula subtracts 5 calories per year of age. Impact: A 20-year age difference changes TDEE by ~120-150 calories at moderate activity. Note: Active older adults who maintain muscle mass may have higher actual TDEE than calculated.
- Sex (Biological):Men receive +5 in the formula; women receive -161. This ~166 calorie difference accounts for typical muscle mass and hormonal differences. Impact: Same-size male vs. female differs by ~200 calories at TDEE level. Note: Transgender individuals on HRT may consider using the sex matching their current hormonal profile.
- Height (cm or ft/in):Taller bodies have more tissue requiring energy. Adds 6.25 calories per centimeter. Impact: Each inch adds ~16 calories to BMR (~20-25 to TDEE). Tip: Measure in the morning; spinal compression makes you slightly shorter by evening.
- Weight (kg or lbs):The largest TDEE driver. Adds 10 calories per kilogram to BMR. Impact: 10 lbs = ~55-70 calorie TDEE difference. Accuracy tip: Use 7-day morning average weight (after bathroom, before eating) for most accurate input. Single-day weights fluctuate 2-5 lbs from water.
- Body Fat % (optional):Enables Katch-McArdle formula using Lean Body Mass. Impact: Two 180 lb people—15% vs 30% body fat—have TDEEs differing by 400-500 calories because muscle is metabolically active. Measurement methods by accuracy: DEXA (±1-2%), hydrostatic (±2-3%), calipers (±3-4%), bioelectrical impedance (±4-8%), visual estimate (±5-10%).
- Activity Level:Sedentary (×1.2): Desk job, <5,000 steps, no exercise. Lightly Active (×1.375): 5,000-7,500 steps OR light exercise 1-3×/week. Moderate (×1.55): 7,500-10,000 steps AND exercise 3-5×/week. Very Active (×1.725): 10,000+ steps AND hard exercise 6-7×/week. Athlete (×1.9): Physical job + daily training. Critical: Most people overestimate—when uncertain, choose one level lower.
- Goal (Lose/Maintain/Gain):Lose weight: Subtracts 15-25% from TDEE. Maintain: Uses exact TDEE. Gain muscle: Adds 10-20% to TDEE. Rate slider: Adjusts deficit/surplus size. Faster rates increase muscle loss risk (deficit) or fat gain (surplus). Conservative rates (0.5-0.75%/week) preserve body composition.
Each input directly affects your calculated TDEE. Understanding why each field matters helps you provide accurate data and interpret results correctly.
The Formulas: Complete Mathematical Reference
BMR & TDEE Calculation Methods
- Mifflin-St Jeor (1990) — Default:
W = weight (kg), H = height (cm), A = age (years). Accurate within ±10% for ~80% of general population.
- Harris-Benedict (Revised 1984):
Estimates 5-10% higher than Mifflin-St Jeor. Useful for muscular individuals without body fat data.
- Katch-McArdle (1996):
LBM = Weight (kg) × (1 − Body Fat %). Most accurate (±5%) when body fat is reliably measured. Ideal for athletes.
- TDEE & Goal Calculations:TDEE = BMR × Activity Multiplier
Weight Loss Target = TDEE × (1 - Deficit %)
Weight Gain Target = TDEE × (1 + Surplus %)Example: BMR 1,600 × 1.55 (moderate) = 2,480 TDEE. For 20% deficit: 2,480 × 0.80 = 1,984 daily target. Never go below BMR.
Three peer-reviewed formulas estimate Basal Metabolic Rate (BMR). TDEE multiplies BMR by activity factor. Understanding the math helps you trust—and verify—results.
Interpreting Your Results: What the Numbers Mean
Output Interpretation Guide
- BMR (Basal Metabolic Rate):Calories burned at complete rest—your "survival minimum." Typical ranges: Women: 1,200-1,600. Men: 1,400-1,900. Red flag: Calculated BMR below 1,200 (women) or 1,400 (men) suggests input error or need for clinical evaluation. Critical rule: Never eat below BMR for extended periods—this triggers severe adaptation and muscle loss.
- TDEE (Total Daily Energy Expenditure):Your actual daily calorie burn—the number you diet from. Typical ranges: Sedentary: 1,600-2,200. Active: 2,000-3,000. Athletic: 2,500-4,500+. Validation method: Eat at calculated TDEE for 2 weeks. If weight stable (±1 lb), number is correct. Gaining? Reduce 10%. Losing? Increase 10%.
- Target Calories (Goal-Adjusted):TDEE modified for your goal. Weight loss: Expect 0.5-1% body weight loss per week on proper deficit. Faster = muscle loss risk. Maintenance: Weight stable within ±2 lbs (water fluctuation). Muscle gain: Expect 0.25-0.5% body weight gain per week. Faster = excess fat gain.
- Macro Targets (P/C/F grams):Protein: Most critical—hit this target daily for muscle retention/growth. Carbs & Fats: More flexible; adjust based on energy, training, and preference. Calorie math: Protein × 4 + Carbs × 4 + Fat × 9 = Total Calories. Small rounding differences are normal.
- Zig-Zag Schedule:Daily calorie targets that vary while maintaining weekly average. High days: Training days, social events, higher energy needs. Low days: Rest days, lower activity. Weekly total: Should match Target × 7. If following zig-zag, focus on weekly average rather than daily precision.
Calculator outputs require context to be actionable. Here's how to interpret each value and what to do with the information.
Common Calculation Pitfalls & Edge Cases
Avoiding Errors That Sabotage Results
- Activity Level Overestimation:The #1 error. A 30-minute gym session 4×/week does NOT make you "Moderately Active"—that requires exercise PLUS 7,500-10,000 daily steps. Most desk workers with regular gym routines are "Lightly Active." Test: Track steps for a week. Under 7,500 average = Sedentary or Light regardless of gym time.
- Eating Back Exercise Calories:Activity multipliers already include exercise. Adding calories for a workout on top of TDEE double-counts. Fitness trackers overestimate burns by 30-50%. Exception: Endurance training 2+ hours may require separate fueling—but most people don't need this.
- Ignoring Weekend Intake:Many track Mon-Fri perfectly but estimate weekends. A 2-day surplus easily erases a 5-day deficit. Solution: Track everything for at least 2 weeks initially, including weekends and alcohol. Social eating is where most diets fail mathematically.
- Using Scale Weight as Sole Metric:Weight fluctuates 2-5 lbs daily from water, sodium, carbs, and menstrual cycle. Don't adjust calories based on single-day changes. Solution: Use 7-day rolling average. Only consider TDEE adjustment if 2-week average trends contrary to goal.
- Extreme Starting Deficits:Jumping to a 1,000+ calorie deficit creates severe adaptation, muscle loss, and inevitable rebound. Your body responds by reducing BMR and NEAT. Better approach: Start with 15-20% deficit. If progress stalls after 4-6 weeks, reduce by another 100-150 cal—not all at once.
- Never Taking Diet Breaks:Continuous restriction for 12+ weeks maximizes metabolic adaptation. Hunger hormones (leptin, ghrelin) shift significantly. Solution: Every 8-12 weeks, spend 1-2 weeks at maintenance calories. This partially resets hormones and allows metabolic rate recovery before continuing deficit.
Even accurate formulas produce misleading results with incorrect inputs or misapplied assumptions. Here are the most common issues.
Putting It All Together: Practical Implementation
Step-by-Step Application Guide
- Week 1-2: Validate Your TDEE:Eat at calculated maintenance (TDEE). Track everything accurately using food scale. Weigh daily, calculate 7-day average. Outcome: If weight stable (±1 lb), TDEE is accurate. If gaining, reduce by 10%. If losing, increase by 10%. Repeat until stable.
- Week 3+: Implement Your Goal:Fat loss: Reduce to TDEE minus 15-20% (300-500 cal for most). Prioritize protein (0.7-1g/lb body weight). Muscle gain: Increase to TDEE plus 10-15% (200-400 cal). Ensure resistance training program is active. Track rate: Aim for 0.5-1% body weight change per week.
- Ongoing: Monitor & Adjust:Recalculate TDEE every 10-15 lbs of weight change. Watch for adaptation signs: weight stalled 2+ weeks, energy crashing, sleep disrupted, strength declining. Adjustment options: Small calorie reduction (100-150), add movement (steps not gym), or schedule diet break.
- Troubleshooting Stalls:First check: Are you actually tracking accurately? Re-weigh portions for a week. Second check: Activity level correct? Track steps. Third check: How long in deficit? Consider diet break if 8+ weeks. Fourth check: Sleep and stress? Both increase cortisol and water retention, masking fat loss.
- Long-Term Maintenance:After reaching goal, don't jump back to pre-diet eating. "Reverse diet" by adding 100-150 cal/week until reaching new maintenance TDEE (which will be lower than original due to lighter body weight). This rebuilds metabolic rate gradually and prevents rapid regain.
Turning calculator output into a sustainable nutrition plan requires calibration and patience. Here's the evidence-based approach.
FAQ
? How many calories should I eat to lose weight?
Subtract 250-500 calories from your TDEE for sustainable fat loss of 0.5-1 lb/week. A 500-calorie daily deficit creates a 3,500-calorie weekly deficit (~1 lb fat). Never eat below your BMR (typically 1,200-1,500 for women, 1,400-1,800 for men). The calculator shows both TDEE and recommended deficit targets automatically.
? How accurate is this calorie calculator?
The Mifflin-St Jeor formula is accurate within ±10% (~150-250 calories) for 80% of the general population. Katch-McArdle improves to ±5% when body fat is accurately measured. The biggest accuracy factor is activity level selection—most people overestimate by one level. Validate your TDEE by eating at the calculated maintenance for 2 weeks; if weight is stable (±1 lb), the number is correct.
? Should I eat back exercise calories?
No. Exercise is already factored into your Activity Level multiplier. Fitness trackers overestimate exercise calories by 30-50%. If you add a new workout routine, move up one activity level rather than manually adding calories. Exception: endurance athletes training 2+ hours daily may need separate fueling calculations.
? Why did my weight loss plateau?
Three common causes: (1) Metabolic adaptation—after 8+ weeks of deficit, your body reduces BMR and NEAT (unconscious movement) by 10-15%. (2) Calorie creep—portion sizes gradually increase without realizing. (3) Activity reduction—you move less outside the gym when dieting. Solutions: take a 1-2 week diet break at maintenance, re-weigh portions, and track daily steps.
? What macro split should I use?
Priority order: (1) Hit protein target first—0.7-1g per pound body weight for muscle retention. (2) Fill remaining calories with carbs and fats based on preference. Common splits: Balanced (30P/40C/30F), High Protein (35P/35C/30F), Low Carb (35P/25C/40F). Total calories matter more than carb/fat ratio for weight change; protein matters most for body composition.
? Is 1,200 calories safe?
1,200 calories is the absolute minimum for women and generally unsafe for men (1,500 minimum). At these levels: micronutrient deficiency is likely, muscle loss accelerates, metabolic adaptation is severe, and long-term adherence is poor. If your calculated deficit lands below minimums, increase activity rather than eating less. Very Low Calorie Diets (<800 cal) require medical supervision.
? How often should I recalculate?
Every 10-15 pounds of weight change. As you lose weight, your body requires fewer calories—a 150 lb person has ~150 calories lower TDEE than at 170 lbs. Also recalculate if: activity level changes significantly, you switch jobs, you recover from injury, or weight loss stalls for 3+ weeks despite accurate tracking.
? What is zig-zag calorie cycling?
Varying daily calories while maintaining the same weekly average. Instead of 1,800 cal/day (12,600/week), you might eat 1,600 on rest days and 2,100 on training days. Benefits: prevents full metabolic adaptation, matches fuel to training demands, improves psychological adherence, and allows flexibility for social events. Most effective for those 8+ weeks into a diet.