Overview
TDEE.page estimates resting energy needs, multiplies that estimate by an activity factor, and then applies the selected calorie goal. The output is an educational starting point, not an exact measurement or medical recommendation.
All calculator inputs are processed locally in your browser. The app does not require an account and does not store calculator inputs on a server.
Formula Inputs and Gender Coefficients
The Mifflin-St Jeor and Revised Harris-Benedict equations use male/female coefficients from their published formulas. The form labels this field as Gender for readability, but internally the selected option is used only to choose the equation coefficient. The calculator cannot model all individual biological variation.
Mifflin-St Jeor Equation
This is the default equation for most adult users because it is widely cited and performed well in comparisons against measured resting metabolic rate.
Male: BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age + 5
Female: BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age - 161
Revised Harris-Benedict Equation
This option uses the 1984 Roza and Shizgal revision of the original Harris-Benedict equation.
Male: BMR = 88.362 + 13.397 x weight(kg) + 4.799 x height(cm) - 5.677 x age
Female: BMR = 447.593 + 9.247 x weight(kg) + 3.098 x height(cm) - 4.330 x age
Katch-McArdle Equation
Katch-McArdle estimates resting needs from lean body mass. It is only available when body fat percentage is entered. If body fat is guessed poorly, this equation can be less useful than the default.
Lean body mass = weight(kg) x (1 - body fat percentage / 100)
BMR = 370 + 21.6 x lean body mass(kg)
Unit Conversion Logic
1 lb = 0.453592 kg
1 inch = 2.54 cm
Height(cm) = (feet x 12 + inches) x 2.54
Activity Multipliers
Estimated TDEE is calculated as BMR multiplied by the selected activity factor.
| Level | Factor | Description |
|---|---|---|
| Sedentary | 1.2 | Little exercise; mostly sitting |
| Lightly Active | 1.375 | Light exercise or regular walking 1-3 days/week |
| Moderately Active | 1.55 | Moderate exercise 3-5 days/week |
| Very Active | 1.725 | Hard exercise 6-7 days/week or active job |
| Extra Active | 1.9 | Physical job plus high training load |
These are broad categories. If you are unsure, start conservative and adjust after observing real-world progress.
Goal Calories
Goal calories are a percentage adjustment from estimated TDEE:
| Goal | Calculation |
|---|---|
| Maintain | 100% of estimated TDEE |
| Mild deficit | 90% of estimated TDEE (-10%) |
| Moderate deficit | 85% of estimated TDEE (-15%) |
| Larger deficit | 80% of estimated TDEE (-20%) |
| Mild surplus | 105% of estimated TDEE (+5%) |
| Moderate surplus | 110% of estimated TDEE (+10%) |
| Larger surplus | 115% of estimated TDEE (+15%) |
Macro Calculation
Macros use goal-adjusted calories and body weight. Protein is set first, fat is set as a percentage of calories, and carbohydrates receive the remaining calories.
- Balanced: protein 1.8 g/kg, fat 27.5% of calories.
- Higher Protein: protein 2.2 g/kg, fat 25% of calories.
- Lower Fat: protein 1.8 g/kg, fat 20% of calories.
- Lower Carb: protein 2.0 g/kg, fat 40% of calories.
These presets are educational estimates. They do not replace individualized nutrition advice.
Rounding and Estimate Range
- Displayed calories are rounded to the nearest 5 kcal.
- The practical TDEE range is shown as +/-10% of estimated TDEE.
- The weekly direction in the result panel uses the simplified 3,500 kcal per pound heuristic and is shown only as context.
Safety Limits
The calculator warns when goal calories fall below 1,500 kcal/day for male coefficients or 1,200 kcal/day for female coefficients. This warning is intentionally conservative and does not determine whether a target is medically appropriate for you.
Seek qualified guidance if you are under 18, pregnant or lactating, managing diabetes, thyroid disease, metabolic disease, an eating disorder history, medical weight management, or elite training demands.
Limitations
- Predictive equations estimate population averages, not exact individual needs.
- Activity multipliers are coarse and self-reported activity is often inaccurate.
- Food labels, portion estimates, and tracking consistency add measurement error.
- Energy expenditure can change with weight loss, training load, sleep, stress, and illness.
Use the result as a starting point. Track weight averages and energy for 2-4 weeks, then adjust gradually if needed.
References
- National Academies of Sciences, Engineering, and Medicine — Factors Affecting Energy Expenditure and Requirements. Dietary Reference Intakes for Energy — NCBI Bookshelf, 2023.Used for TDEE components, REE variability, thermic effect of food, and equation limitations.
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO — A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-247, 1990.Used for the Mifflin-St Jeor resting energy expenditure equation and its study population.
- Roza AM, Shizgal HM — The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass. Am J Clin Nutr. 1984;40(1):168-182, 1984.Used for the revised Harris-Benedict coefficients implemented in the calculator.
- McArdle WD, Katch FI, Katch VL — Exercise Physiology: Energy, Nutrition, and Human Performance. Lippincott Williams & Wilkins, 7th edition, 2010.Used only for formula provenance of the lean-body-mass-based Katch-McArdle estimate.
- Frankenfield D, Roth-Yousey L, Compher C — Comparison of Predictive Equations for Resting Metabolic Rate in Healthy Nonobese and Obese Adults. J Am Diet Assoc. 2005;105(5):775-789, 2005.Used for cautious comparison of predictive equation error against measured resting metabolic rate.
- Chao AM, Tronieri JS, Alamuddin N, Wadden TA — Behavioral Approaches to Obesity Management. Endotext — NCBI Bookshelf, 2026.Used for evidence-aware wording around typical calorie deficits in structured behavioral weight-management programs.
- Institute of Medicine — Acceptable Macronutrient Distribution Ranges. Dietary Reference Intakes: Guiding Principles for Nutrition Labeling and Fortification, 2003.Used for adult AMDR context for fat, carbohydrate, and protein percentages.
- Jager R, Kerksick CM, Campbell BI, et al. — International Society of Sports Nutrition Position Stand: Protein and Exercise. J Int Soc Sports Nutr. 2017;14:20, 2017.Used for protein intake context in healthy exercising adults.
Questions or Corrections
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