Maintenance Calorie Calculator (TDEE)

Maintaining your weight is a delicate balance between the energy you consume through food and the energy your body expends through basic biological functions and physical movement. This calculator helps you determine your Total Daily Energy Expenditure (TDEE), commonly known as your "maintenance calories."

What is TDEE?

TDEE is the total number of calories your body burns in a 24-hour period. It consists of four main components:

1. Basal Metabolic Rate (BMR): The calories burned at rest to keep your heart beating and lungs breathing.
2. Thermic Effect of Food (TEF): Energy used to digest and process nutrients.
3. Non-Exercise Activity Thermogenesis (NEAT): Energy spent on daily movement like walking, fidgeting, or cleaning.
4. Thermic Effect of Activity (TEA): Energy spent during intentional exercise.

The Formulas

This calculator utilizes the two most scientifically validated equations for estimating BMR:

1. Mifflin-St Jeor Equation

Considered the most accurate for the general population in modern clinical settings.

$BMR (Men) = (10 \times weight\text{ kg}) + (6.25 \times height\text{ cm}) - (5 \times age) + 5$ $BMR (Women) = (10 \times weight\text{ kg}) + (6.25 \times height\text{ cm}) - (5 \times age) - 161$

2. Revised Harris-Benedict Equation

An older but still widely used formula that was revised in 1984 for better accuracy.

$BMR (Men) = 88.362 + (13.397 \times weight\text{ kg}) + (4.799 \times height\text{ cm}) - (5.677 \times age)$ $BMR (Women) = 447.593 + (9.247 \times weight\text{ kg}) + (3.098 \times height\text{ cm}) - (4.330 \times age)$

Activity Multipliers

Once the BMR is calculated, we apply a multiplier based on your lifestyle:

• Sedentary: BMR × 1.2 (Office job, little exercise)
• Lightly Active: BMR × 1.375 (1–3 days of light exercise/week)
• Moderately Active: BMR × 1.55 (3–5 days of moderate exercise/week)
• Very Active: BMR × 1.725 (6–7 days of hard exercise/week)
• Extra Active: BMR × 1.9 (Physical job or 2x daily training)

How to Use This Calculator

1. Select Gender: Biological factors influence metabolic rates.
2. Enter Age: Metabolism naturally slows slightly as we age.
3. Input Weight & Height: Use the toggle to switch between Metric (kg/cm) and Imperial (lb/in) units.
4. Choose Activity Level: Be honest! Most people overestimate their activity level.
5. Review Results: See your TDEE, BMI, and a breakdown of calories needed for weight loss or gain.

Worked Example

Profile: Male, 30 years old, 80kg, 180cm, Moderately Active.

1. Calculate BMR (Mifflin):
   • $(10 \times 80) + (6.25 \times 180) - (5 \times 30) + 5$
   • $800 + 1125 - 150 + 5 = 1780$ kcal.
2. Apply Activity Multiplier:
   • $1780 \times 1.55 = 2759$ kcal.
3. Result: To maintain 80kg, this individual needs approximately 2,759 calories per day.

FAQ

How accurate is this calculator?

While these formulas are clinically validated, they are estimates. Individual metabolic rates can vary by 10-15% based on muscle mass, genetics, and hormonal health.

Should I use Mifflin-St Jeor or Harris-Benedict?

For most people, Mifflin-St Jeor is the current gold standard. However, if you are very lean or very muscular, the Katch-McArdle formula (which requires body fat percentage) might be more accurate.

Why is my BMI included?

BMI provides a general health context. If your BMI is high, your maintenance calories might be higher due to the energy required to move a larger body mass, but weight loss might be recommended for long-term health.

Does muscle mass affect maintenance calories?

Yes. Muscle is more metabolically active than fat. Two people with the same weight but different body fat percentages will have different maintenance calories.

How often should I recalculate?

Recalculate every time you lose or gain 2-5kg, as your metabolic needs will change with your body mass.

Disclaimer

This tool is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional or registered dietitian before making significant changes to your diet or exercise routine.