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Maintenance Calorie Calculator (Tdee)

Calculate your Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor equation. Enter age, weight, height, and activity level to find your daily maintenance calories.

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Maintenance Calories (TDEE)

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Maintenance Calories (TDEE)—kcal/day

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What Is a Maintenance Calorie Calculator (TDEE)?

A maintenance calorie calculator estimates Total Daily Energy Expenditure (TDEE) — the precise number of calories the body burns each day across all activities to maintain current body weight. TDEE serves as the nutritional baseline for any effective diet plan: eating at TDEE preserves weight, eating below it produces a caloric deficit for fat loss, and eating above it creates a surplus for muscle gain. Accurately knowing this number removes the guesswork from calorie targets.

The Mifflin-St Jeor Equation Explained

This calculator applies the Mifflin-St Jeor equation, first published in 1990 and consistently validated as the most accurate BMR prediction formula for non-athlete adults. The formula calculates Basal Metabolic Rate (BMR) — the calories required to sustain life at complete rest — before multiplying by an activity factor to arrive at TDEE. The equation uses four variables:

  • w — body weight in kilograms
  • h — height in centimeters
  • a — age in completed years
  • s — biological sex constant: +5 for males, −161 for females

The BMR component of the formula is: BMR = (10 × w) + (6.25 × h) − (5 × a) + s

TDEE is then obtained by multiplying BMR by the appropriate Activity Factor (AF): TDEE = BMR × AF

The sex constant accounts for the average difference in lean body mass between biological males and females at equivalent heights and weights. The age subtraction of 5 kcal per year reflects the documented decline in resting metabolism as muscle mass decreases with age, as described in research published by Harvard Medical School.

Activity Level Multipliers (AF Values)

The Activity Factor translates resting metabolism into real-world energy expenditure. Selecting the correct tier is critical — overestimating activity is the most common source of error in TDEE calculations:

  • Sedentary (AF = 1.2) — Desk job or largely inactive lifestyle with little to no structured exercise
  • Lightly Active (AF = 1.375) — Light exercise or recreational activity 1–3 days per week
  • Moderately Active (AF = 1.55) — Moderate cardiovascular or strength training 3–5 days per week
  • Very Active (AF = 1.725) — Hard training sessions or competitive sports 6–7 days per week
  • Extra Active (AF = 1.9) — Physically demanding occupation combined with daily intense exercise or two-a-day training sessions

Worked Example: Male

A 30-year-old male weighing 75 kg, standing 175 cm tall, with a moderately active lifestyle:

  • BMR = (10 × 75) + (6.25 × 175) − (5 × 30) + 5 = 750 + 1,093.75 − 150 + 5 = 1,698.75 kcal/day
  • TDEE = 1,698.75 × 1.55 = 2,633 kcal/day

To lose approximately 0.45 kg (1 lb) per week, this individual would target roughly 2,133 kcal/day.

Worked Example: Female

A 28-year-old female weighing 60 kg, standing 165 cm tall, with a lightly active lifestyle:

  • BMR = (10 × 60) + (6.25 × 165) − (5 × 28) − 161 = 600 + 1,031.25 − 140 − 161 = 1,330.25 kcal/day
  • TDEE = 1,330.25 × 1.375 = 1,829 kcal/day

Metric and Imperial Unit Support

Both metric (kg, cm) and imperial (lb, in) inputs are accepted. Imperial values are automatically converted before the formula runs: body weight is divided by 2.205 to produce kilograms, and height in inches is multiplied by 2.54 to produce centimeters. The final TDEE output is expressed in kilocalories (kcal), the standard unit used on food nutrition labels worldwide.

Practical Applications of TDEE

According to Harvard Health Publishing, calorie awareness is central to sustained weight management. With a known TDEE, common targets become straightforward: a 500 kcal/day deficit produces roughly 0.45 kg (1 lb) of fat loss per week, while a 250–500 kcal/day surplus supports lean muscle gain when paired with resistance training. Research available through the National Institutes of Health (PubMed Central) confirms that energy balance — calories in versus TDEE — remains the primary driver of body weight change in healthy adults.

Accuracy and Limitations

The Mifflin-St Jeor equation estimates TDEE within approximately ±10% for most healthy, non-athlete adults. Individuals with atypically high lean muscle mass (competitive bodybuilders), significant hormonal imbalances, thyroid disorders, or those taking metabolic-affecting medications may see greater deviation. For these populations, indirect calorimetry conducted in a clinical setting provides a more precise measurement. The TDEE result from this calculator is best treated as a starting point: track body weight over 2–4 weeks and adjust calorie intake by 100–200 kcal increments based on observed trends.

Reference

Frequently asked questions

What is TDEE and how does it differ from BMR?
BMR (Basal Metabolic Rate) is the number of calories burned at complete rest — the energy required just to keep organs functioning. TDEE (Total Daily Energy Expenditure) builds on BMR by multiplying it by an activity factor to account for movement, exercise, and the thermic effect of food. For most adults, TDEE is 20–90% higher than BMR. Maintenance calories equal TDEE, not BMR, making TDEE the correct target for any diet plan.
How accurate is the Mifflin-St Jeor equation used in this maintenance calorie calculator?
The Mifflin-St Jeor equation, validated across multiple independent studies since its 1990 publication, estimates BMR within approximately 10% for most healthy adults and outperforms older formulas such as the Harris-Benedict equation in head-to-head accuracy trials. Accuracy is lower for individuals with extremely high muscle mass, severe obesity, thyroid disorders, or age over 70. Tracking body weight weekly and adjusting calorie intake based on real-world results improves precision beyond any formula alone.
Which activity level should be selected when using the TDEE calculator?
Select the tier that honestly represents the average week rather than the best week. Sedentary (1.2) applies to desk workers with no structured exercise. Lightly active (1.375) suits 1–3 workout days per week. Moderately active (1.55) covers consistent exercise 3–5 days per week. Very active (1.725) fits 6–7 hard training days weekly. Extra active (1.9) is reserved for athletes or manual laborers who also train intensely every day. Most people overestimate their activity level, so starting one tier lower and adjusting based on weight trends is often advisable.
How many calories below maintenance calories should be consumed to lose weight?
One pound (approximately 0.45 kg) of body fat stores roughly 3,500 kcal of energy. A daily deficit of 500 kcal below TDEE therefore produces approximately 0.45 kg of fat loss per week, while a 250 kcal daily deficit yields roughly 0.23 kg per week. Deficits exceeding 1,000 kcal per day are generally not recommended without medical supervision, as they increase the risk of lean muscle loss, micronutrient deficiencies, and metabolic adaptation that slows further progress.
Can the maintenance calorie calculator be used to plan a muscle-gain diet?
Yes. After calculating TDEE as the maintenance baseline, add a controlled caloric surplus of 250–500 kcal per day to support muscle hypertrophy without excessive fat gain. A 250 kcal surplus is appropriate for a lean bulk, while 500 kcal suits faster muscle gain phases. Combine the surplus with a high-protein intake of 1.6–2.2 g per kilogram of body weight per day and a structured progressive overload resistance training program to maximize the ratio of muscle to fat gained during the surplus period.
How does age affect TDEE and daily calorie requirements?
The Mifflin-St Jeor equation subtracts 5 kcal for every year of age via the '−5a' term, capturing the well-documented decline in resting metabolism driven primarily by age-related muscle loss (sarcopenia). A sedentary 50-year-old of identical weight, height, and sex has an estimated BMR roughly 100 kcal lower than a 30-year-old. Regular resistance training and adequate protein intake (1.2–1.6 g/kg/day) are the most effective strategies to preserve muscle mass and partially counteract this age-related reduction in daily calorie needs.