How this TDEE calculator works
Your total daily energy expenditure is estimated in two steps. First, a regression equation predicts your basal metabolic rate (BMR), the energy needed to keep you alive at complete rest. Then BMR is multiplied by an activity factor that covers digestion, everyday movement and training.
Choosing a goal
Published recommendations for people who lift usually favor slow, controlled changes. Losing about 0.5–1% of body weight per week when cutting preserves more lean mass than crash dieting, and a small surplus when bulking limits fat gain. The goal presets apply a percentage to your maintenance calories rather than a fixed number, so they scale with body size.
Calibrate with real data
Treat the number as a hypothesis. Weigh yourself under the same conditions on most mornings, compare weekly averages, and adjust intake by 100–200 kcal if the trend doesn't match the goal after 2–3 weeks. Your own data will beat any equation.
Frequently asked questions
What is TDEE?
Total Daily Energy Expenditure is the estimated number of calories you burn in a day: your basal metabolic rate (BMR) plus the energy used for digestion, daily movement and exercise. Eating at your TDEE should, on average, keep your weight stable.
Which BMR formula is the most accurate?
In validation studies the Mifflin-St Jeor equation has generally predicted resting metabolic rate within ±10% for more adults than older equations, which is why we use it as the default. If you know your body-fat percentage, lean-mass equations such as Katch-McArdle or Cunningham can suit muscular people better.
How many calories should I eat to lose fat without losing muscle?
Reviews on physique athletes commonly suggest a moderate deficit that produces roughly 0.5–1% of body weight lost per week, combined with high protein intake and resistance training. That usually corresponds to a 10–25% calorie reduction from maintenance.
Why is my real maintenance different from the calculator?
Every equation is a population average. Genetics, non-exercise movement (NEAT), measurement errors and adaptive changes all shift real expenditure. Use the result as a starting point, track body weight for 2–3 weeks, and adjust by 100–200 kcal based on the trend.
Should I eat back the calories I burn exercising?
Not if the activity level you picked already includes your training. The activity multiplier accounts for it. Adding fitness-tracker calories on top is a common cause of overeating, because wearables tend to overestimate exercise expenditure.
Sources & further reading
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO (1990). A new predictive equation for resting energy expenditure in healthy individuals . Am J Clin Nutr 51(2):241–247 · doi:10.1093/ajcn/51.2.241
- Roza AM, Shizgal HM (1984). The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass . Am J Clin Nutr 40(1):168–182 · doi:10.1093/ajcn/40.1.168
- Frankenfield D, Roth-Yousey L, Compher C (2005). Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review . J Am Diet Assoc 105(5):775–789 · doi:10.1016/j.jada.2005.02.005
- Cunningham JJ (1980). A reanalysis of the factors influencing basal metabolic rate in normal adults . Am J Clin Nutr 33(11):2372–2374 · doi:10.1093/ajcn/33.11.2372
- Helms ER, Aragon AA, Fitschen PJ (2014). Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation . J Int Soc Sports Nutr 11:20 · doi:10.1186/1550-2783-11-20