What This Tool Does
This TDEE calculator applies the Mifflin-St Jeor equation — the most validated BMR formula in clinical nutrition research — then multiplies by a precise activity factor to produce your total daily energy expenditure. It also outputs goal-specific calorie targets for fat loss (500-calorie deficit) and lean bulking (300-calorie surplus), plus a macro split, giving you a complete nutrition baseline in one calculation.
How to Get Accurate Results
- Weigh yourself first thing in the morning after using the bathroom, before eating. This eliminates water and food weight fluctuations that can skew your BMR calculation by 3-5%.
- Be honest about activity level. Most people overestimate. If you exercise 3 days per week but sit at a desk the rest, choose "Lightly Active" — not "Moderately Active."
- Track actual weight change for 2-3 weeks at your calculated maintenance calories. If weight holds steady, the estimate is accurate. Adjust by 100-200 calories if it drifts.
Methodology
BMR is computed as 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161 for females, with +5 replacing −161 for males. This Mifflin-St Jeor equation was validated in a 2005 meta-analysis as the most accurate predictive BMR formula for non-obese adults. TDEE multiplies BMR by an activity factor: 1.2 (sedentary), 1.375 (light), 1.55 (moderate), 1.725 (active), or 1.9 (very active). Weight-loss calories subtract 500 from TDEE, targeting approximately 1 lb/week fat loss based on the 3,500-calorie-per-pound principle. Bulking adds 300 calories for lean muscle synthesis. The macro split allocates 30% protein, 35% carbs, and 35% fat, converted to grams using 4 cal/g for protein and carbs and 9 cal/g for fat.
Real-World Application
Sports dietitians use TDEE calculations to build periodized nutrition plans for competitive athletes. By recalculating TDEE each training phase — off-season bulk, pre-competition cut, and race week — they match calorie intake to energy demand and prevent the performance drops caused by underfueling or uncontrolled weight gain.
Frequently Asked Questions
What is TDEE and how is it calculated?
TDEE (Total Daily Energy Expenditure) is the total number of calories your body burns in a day, including basal metabolic rate (BMR) and physical activity. Our calculator uses the Mifflin-St Jeor equation to calculate BMR, then multiplies by your activity level factor. For example, a moderately active person multiplies their BMR by 1.55 to determine maintenance calories.
How accurate is this TDEE calculator?
This TDEE calculator provides an accurate estimate within 10% for most individuals using the scientifically-validated Mifflin-St Jeor equation. However, actual energy expenditure varies based on genetics, muscle mass, and metabolic adaptations. Track your weight for 2-3 weeks and adjust calorie intake based on real-world results for optimal accuracy.
What is the difference between BMR and TDEE?
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest for basic functions like breathing and circulation. TDEE is your total daily energy expenditure including BMR plus calories burned through activity, exercise, and digestion. Your TDEE is always higher than BMR—typically 1.2x to 1.9x depending on activity level.
How many calories should I eat to lose weight?
For sustainable weight loss, eat 300-500 calories below your TDEE. A 500-calorie daily deficit leads to approximately 1 pound of fat loss per week. Our calculator automatically suggests deficit calories for weight loss goals. Avoid eating below your BMR, as this can slow metabolism and cause muscle loss. Combine calorie deficit with strength training for best results.
What TDEE calculator activity level should I choose?
Choose sedentary for desk jobs with minimal exercise, lightly active for 1-3 workout days per week, moderately active for 3-5 days, very active for daily exercise, and extremely active for athletes or physical jobs. Most people overestimate activity—if unsure, start with a lower level and adjust based on weight changes. This approach ensures accurate maintenance calorie calculations.
How many calories do I need for bulking?
For lean bulking (muscle gain with minimal fat), eat 200-300 calories above your TDEE. This creates a small surplus for muscle synthesis while limiting fat gain. Bodybuilders and athletes should consume 0.5-1g protein per pound of body weight and increase calories gradually. Track weight weekly—aim for 0.5-1 pound gain per month for optimal muscle building without excessive fat.
Should I use metric or imperial units for TDEE?
Both metric (kg, cm) and imperial (lbs, feet/inches) units provide identical TDEE calculations—choose whichever you're comfortable with. The calculator converts imperial to metric internally using the same Mifflin-St Jeor formula. Metric measurements are standard in scientific literature, while imperial is common in the United States. Results accuracy is the same regardless of unit system.
How often should I recalculate my TDEE?
Recalculate your TDEE every 10-15 pounds of weight change or when activity levels shift significantly. As you lose weight, your maintenance calories decrease since there's less body mass to fuel. Athletes should recalculate when training volume changes. Use this online calculator monthly to adjust calorie targets and ensure continued progress toward weight loss or muscle gain goals.
About the Creator
Tool developed by Tyler, founder of ToolVault. Building professional-grade web utilities since 2025 to help creators and business owners make data-driven decisions. This tool is designed for private, browser-based accuracy.