What Is TDEE?
TDEE stands for Total Daily Energy Expenditure: the energy your body uses across a day for resting functions, digestion, daily movement, and exercise. Estimated TDEE is commonly used as a starting point for maintenance-calorie planning.
This calculator first estimates resting energy with the Mifflin-St Jeor equation, then multiplies it by a conventional activity factor. The multiplier is a practical shortcut—not a direct measurement—so two people with the same inputs can still have different energy needs.
BMR, RMR, and Resting Energy
BMR and RMR both describe energy used at rest, but they are measured under different laboratory conditions. Mifflin-St Jeor was developed as a predictive equation for resting energy expenditure, so “RMR estimate” is the more precise label for this result. Many consumer calculators still call it BMR, which is why both terms appear on this page.
The result is an estimate from age, weight, height, and the equation’s sex coefficient. Indirect calorimetry is used when a measured resting metabolic rate is clinically important.
What Is the Mifflin-St Jeor Formula?
The equation was published in 1990 from data collected from 498 healthy adults aged 19–78. It remains a widely used resting-energy estimate, but validation research shows that prediction error varies between individuals and populations.
Men: estimated RMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) + 5 Women: estimated RMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) − 161 TDEE estimate = RMR estimate × activity multiplier
Source: Mifflin et al., American Journal of Clinical Nutrition ↗
Understanding Activity Multipliers
Activity multipliers combine exercise and ordinary daily movement into one rough factor. Choose the description closest to your overall week rather than selecting a level from workouts alone.
| Level | Factor | General pattern |
|---|---|---|
| Sedentary | 1.2× | Little or no exercise, desk job |
| Lightly Active | 1.375× | Light exercise 1–3 days/week |
| Moderately Active | 1.55× | Moderate exercise 3–5 days/week |
| Very Active | 1.725× | Hard exercise 6–7 days/week |
| Extremely Active | 1.9× | Hard daily exercise + physical job |
The factors are conventional planning heuristics. They are not wearable measurements and cannot capture every difference in occupation, step count, training volume, or movement efficiency.
Using a TDEE Estimate for Weight Loss
The calculator shows gentle and moderate starting targets at 10% and 20% below estimated maintenance. These percentages scale with the individual instead of subtracting the same fixed number from everyone.
Do not treat the calorie difference as a guaranteed rate of fat loss. Body weight changes dynamically as energy expenditure, water, appetite, and body composition change. The NIH Body Weight Planner uses a dynamic model for this reason. The CDC recommends gradual, steady weight loss and notes that medicines, medical conditions, stress, genes, hormones, environment, and age can affect weight management.
Further reading: NIDDK Body Weight Planner research ↗ and CDC weight-loss guidance ↗.
Using a TDEE Estimate for Weight Gain
The +5% and +10% targets are planning examples, not predictions of muscle gain. Training programme, experience, sleep, protein intake, genetics, and the accuracy of the maintenance estimate all influence whether a surplus supports muscle, fat, or both.
Track your average body weight and performance over several weeks before changing calories. A single day—or even a single week—can be distorted by hydration, sodium, glycogen, digestion, and menstrual-cycle changes.
How to Calibrate Your Maintenance Calories
Use the calculated TDEE as a starting estimate. Record calorie intake consistently and compare rolling average body weight over two to four weeks. If the trend rises or falls when you intended to maintain, adjust the estimate gradually and repeat.
This real-world feedback captures factors the equation cannot know, including spontaneous movement, exercise efficiency, tracking error, and individual metabolic variation. Recalculate after a meaningful weight or activity change.
Common TDEE Mistakes
Overestimating Activity
Exercise frequency alone may not reflect the rest of your day. Choose the closest overall pattern and calibrate it against your weight trend.
Treating the Result as Exact
The equation and activity multiplier are estimates. Individual resting energy and daily movement can differ substantially.
Reacting to Daily Scale Changes
Hydration and food mass can hide the underlying trend. Compare consistent rolling averages over multiple weeks.
Never Recalculating
Energy needs can change with body weight, activity, training, health, and other circumstances. Update the estimate when those inputs change.
Continue Your Health & Fitness Workflow
Check your height-to-weight screening category with the Adult BMI Calculator, estimate body composition from tape measurements using the Body Fat Percentage Calculator, or turn a maintenance estimate into a gradual goal timeline with the Calorie Deficit & Weight-Loss Planner. For training sessions, use the Running Pace & Race-Time Calculator. Each result is an educational estimate and should be interpreted in context.
Frequently Asked Questions
Disclaimer: This calculator is for informational and educational use by adults. It is not designed for children, pregnancy, breastfeeding, eating-disorder treatment, or clinical nutrition. Results are population-based estimates, not medical or nutritional advice. Consult a registered dietitian or qualified healthcare professional before making significant dietary or exercise changes.