TDEE Calculator — Daily Calorie Needs from BMR

The calculator works in three steps. First it estimates your Basal Metabolic Rate — the calories your body burns while completely at rest. Two predictive equations are supported, and both are computed every time so you can see them side-by-side:

• Mifflin-St Jeor (1990) — preferred default. Men: 10·kg + 6.25·cm − 5·age + 5. Women: 10·kg + 6.25·cm − 5·age − 161.
• Revised Harris-Benedict (Roza & Shizgal 1984) — shown as a cross-check. Men: 88.362 + 13.397·kg + 4.799·cm − 5.677·age. Women: 447.593 + 9.247·kg + 3.098·cm − 4.330·age.
• Katch-McArdle — optional, uses lean body mass. BMR = 370 + 21.6·LBM, where LBM = weight·(1 − body fat %). Best when you actually know your body-fat percentage from a DEXA, BIA scale, or skinfold caliper.

The Academy of Nutrition and Dietetics evidence-analysis review found Mifflin-St Jeor predicted resting energy expenditure within 10% of indirect-calorimetry measurements in 82% of non-obese subjects and 70% of obese subjects — higher accuracy than Harris-Benedict or Owen. That is why it is the calculator's default.

Step two scales BMR up to TDEE by multiplying by an activity factor. The factors are the ones tabulated in the revised Harris-Benedict literature and adopted by the US Institute of Medicine: 1.2 for sedentary, 1.375 for lightly active, 1.55 for moderate, 1.725 for very active, and 1.9 for extra active. They are meant to represent your average day across the whole week — not your hardest training session. Most desk workers who train three or four times a week land between 1.375 and 1.55.

Step three offsets TDEE to produce four calorie goals: an aggressive cut at −500 kcal/day, a moderate cut at −250 kcal/day, maintenance, and a lean bulk at +300 kcal/day. The weekly weight-change projections use the Wishnofsky (1958) rule of thumb that 3,500 kcal equals roughly one pound (7,700 kcal per kilogram) of body fat. The rule overstates real-world results because the body adapts metabolically as you eat less or move more — so treat the projection as a ceiling, weigh yourself daily, and adjust the target after a fortnight if the trend does not match.

The macro panel splits the selected calorie target into protein, carbohydrate, and fat using Atwater factors (4, 4, and 9 kcal per gram). Cut macros bias toward protein to spare lean mass during a deficit, lean-bulk macros lean on carbs to fuel training, and maintenance is balanced. Anyone on a specific diet (ketogenic, vegetarian, sport-specific) should adjust freely — the calorie total is the load-bearing number, not the split.

• Mifflin MD et al. (1990) — A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr 51:241-7
• Roza AM, Shizgal HM (1984) — The Harris Benedict equation reevaluated. Am J Clin Nutr 40:168-82
• Academy of Nutrition and Dietetics — Adult Weight Management Evidence-Analysis Library (Mifflin-St Jeor accuracy)
• Institute of Medicine (2005) — Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids
• Wishnofsky M (1958) — Caloric equivalents of gained or lost weight. Am J Clin Nutr 6:542-6 (the 3,500 kcal/lb rule)

Formulae and constants on this page were last cross-checked against the primary literature on 2026-05-11. The page is reviewed annually and whenever a major nutrition body (Academy of Nutrition and Dietetics, IOM/NAP, WHO) updates its guidance.