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In the realm of nutrition and weight management, understanding your daily caloric needs is crucial. The Mifflin St Jeor Equation stands out as a reliable method for estimating the basal metabolic rate (BMR) and, subsequently, daily calorie requirements. This article explores the Mifflin St Jeor Calculator, shedding light on how it works and its significance in crafting personalized diet plans.


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Understanding Basal Metabolic Rate (BMR)

BMR represents the number of calories your body needs to perform basic life-sustaining functions, such as breathing, circulation, cell production, and nutrient processing, while at rest. It accounts for the largest portion of your daily caloric expenditure, making accurate BMR calculation essential for anyone looking to manage their weight effectively.


The Science Behind the Equation

Developed in the 1990s, the Mifflin St Jeor Equation emerged from research seeking a more accurate formula to estimate Basal Metabolic Rate (BMR). It considers factors such as age, weight, height, and sex to provide a tailored caloric baseline, which can be adjusted based on activity level to find your Total Daily Energy Expenditure (TDEE).

The Mifflin St Jeor Equation is expressed as:

  • For men: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5
  • For women: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) - 161


From BMR to Daily Calorie Needs

Calculating your BMR is just the first step. To determine your total daily energy expenditure (TDEE), you must factor in your activity level using the Physical Activity Level (PAL) scale, which ranges from sedentary to very active. Multiplying your BMR by the appropriate PAL number provides an estimate of your daily caloric needs to maintain your current weight.


Applications in Nutritional Planning

  1. - Weight Management: By providing an accurate estimate of caloric needs, the calculator aids in creating tailored dietary plans for weight loss, gain, or maintenance.
  2. - Nutritional Assessment: Health professionals use it to assess the nutritional status of individuals and tailor interventions accordingly.
  3. - Fitness Planning: Athletes and fitness enthusiasts can leverage this tool to align their caloric intake with energy expenditure, optimizing performance and recovery.


Applying the Calculator to Your Goals

Whether you aim to lose weight, gain muscle, or maintain your current physique, understanding your caloric needs is the first step. By using the Mifflin St Jeor Calculator to determine your TDEE, you can:

  • - Create a Caloric Deficit: For weight loss, consume fewer calories than your TDEE.
  • - Surplus for Growth: For muscle gain, a caloric surplus is often recommended.
  • - Maintenance: To maintain, aim to match your caloric intake with your TDEE.


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Advantages of the Mifflin St Jeor Equation

  • - Accuracy: Research suggests it's more accurate than older equations like the Harris-Benedict, especially for those with lower body fat percentages.
  • - Personalization: It tailors caloric estimates to your individual body metrics and lifestyle.
  • - Simplicity: The equation requires only basic biometric information, making it easily applicable in various settings
  • - Flexibility: It can be adjusted as you progress in your fitness journey, accommodating changes in weight, age, and activity level.


Practical Tips for Using the Calculator

To utilize the calculator effectively:

  1. - Input accurate biometric data: Ensure the weight, height, and age entered are current and precise.
  2. - Regular Updates: Recalculate your TDEE periodically, especially after significant weight changes.
  3. - Select the appropriate activity level: Choose a multiplier that best reflects your daily physical activity to estimate total daily energy expenditure (TDEE).
  4. - Nutritional Quality: Remember, not all calories are created equal. Prioritize nutrient-dense foods to meet your caloric goals.


Considerations and Limitations

While the Mifflin St Jeor Equation is widely regarded for its accuracy, individual variations in metabolism, muscle mass, and medical conditions can affect its precision. It serves as a starting point, but adjustments may be needed based on personal experience and results.



The Mifflin St Jeor Calculator is a valuable tool for anyone looking to understand their caloric requirements better. By providing a scientific basis for estimating BMR and daily caloric needs, it plays a pivotal role in effective weight management and nutritional planning. As with any tool, consider it a part of a comprehensive approach to health and wellness, always taking into account the nuances of your individual body and lifestyle.

Disclaimer: While the Mifflin St Jeor Equation provides a scientific method for estimating caloric needs, individual factors such as metabolism, medical conditions, and specific health goals can influence your exact requirements. Always consult with a healthcare professional or a registered dietitian for personalized advice.


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  1. 1. 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 Feb;51(2):241-7. doi: 10.1093/ajcn/51.2.241. PMID: 2305711.
  2. 2. Frankenfield D, Roth-Yousey L, Compher C. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. J Am Diet Assoc. 2005 May;105(5):775-89. doi: 10.1016/j.jada.2005.02.005. PMID: 15883556.
  3. 3. Luy SC, Dampil OA. Comparison of the Harris-Benedict Equation, Bioelectrical Impedance Analysis, and Indirect Calorimetry for Measurement of Basal Metabolic Rate among Adult Obese Filipino Patients with Prediabetes or Type 2 Diabetes Mellitus. J ASEAN Fed Endocr Soc. 2018;33(2):152-159. doi: 10.15605/jafes.033.02.07. Epub 2018 Sep 10. PMID: 33442121; PMCID: PMC7784146.
  4. 4. Inch calculator. Mifflin St. Jeor Calculator (TDEE & BMR).

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