Calorie Calculator
Calculate your BMR and TDEE to determine daily caloric needs. Turn targets into meal plans with PrepSmart for stress-free meal prep.
Your Information
VitalMetrics - Calorie Calculator
12/22/2025
Your Results
Calories burned at rest (essential body functions)
Using Mifflin-St Jeor formula
📊 Formula Comparison
Mifflin-St Jeor is generally considered more accurate for modern populations.
Total calories burned per day (including activity)
Suggested Macros
Based on TDEE
How Calorie Calculations Work
Your daily caloric needs are determined by two key measurements:
Basal Metabolic Rate (BMR)
BMR represents the number of calories your body needs to perform essential functions at rest, such as breathing, circulation, and cell production. We use the Mifflin-St Jeor Equation, widely regarded as the most accurate formula for calculating BMR:
Total Daily Energy Expenditure (TDEE)
TDEE is your BMR multiplied by an activity factor that accounts for your exercise and daily movement. This gives you the total number of calories you burn in a day:
The Mifflin-St Jeor Equation was developed in 1990 and has been validated by numerous studies as one of the most accurate predictors of resting energy expenditure in healthy adults.
Understanding Your Results
What is BMR?
Your BMR is the baseline number of calories your body needs just to stay alive. Even when you're sleeping, your body is working hard to maintain vital functions like breathing, blood circulation, and cell repair. This accounts for about 60-75% of your total daily calorie burn.
What is TDEE?
TDEE is your total calorie expenditure including all activities throughout the day. This includes your BMR plus calories burned through exercise, daily activities (walking, cleaning, working), and the thermic effect of food (energy used to digest what you eat). To maintain your current weight, you should consume calories equal to your TDEE.
How Activity Level Affects Results
Your activity level has a significant impact on your daily calorie needs:
- •Sedentary (1.2×): Desk job with little to no exercise
- •Lightly Active (1.375×): Light exercise 1-3 days per week
- •Moderately Active (1.55×): Moderate exercise 3-5 days per week
- •Very Active (1.725×): Hard exercise 6-7 days per week
- •Extra Active (1.9×): Very hard exercise and/or physical job
Goal-Based Adjustments
To change your weight, you need to create a calorie deficit (for weight loss) or surplus (for weight gain):
- •Weight Loss: TDEE - 500 calories = ~1 lb per week loss (3,500 calorie deficit per week)
- •Maintenance: TDEE = maintain current weight
- •Weight Gain: TDEE + 500 calories = ~1 lb per week gain (3,500 calorie surplus per week)
Understanding Macros
The suggested macronutrient breakdown provides a balanced distribution of protein, carbohydrates, and fats:
- •Protein (30%): Essential for muscle maintenance and repair, satiety, and metabolism
- •Carbohydrates (40%): Primary energy source for daily activities and exercise
- •Fats (30%): Important for hormone production, nutrient absorption, and brain health
Using Your Results
1. Track Your Calorie Intake
Use a food tracking app or journal to monitor your daily calorie consumption. Aim to consistently hit your goal calorie target. Be honest and accurate with portion sizes and ingredients.
2. Monitor Your Progress
Weigh yourself weekly at the same time of day (morning is best). Track your weight trends over 2-4 weeks. If you're not seeing the expected results, adjust your calorie intake by 100-200 calories.
3. Consider Macronutrient Distribution
While total calories matter most for weight change, paying attention to macros can improve body composition, energy levels, and satiety. Higher protein intake is particularly beneficial for preserving muscle mass during weight loss.
4. Combine with Exercise
Regular exercise enhances results by burning additional calories, building muscle, improving metabolism, and providing numerous health benefits. Include both cardiovascular exercise and resistance training for optimal results.
5. Be Patient and Consistent
Sustainable weight change takes time. Aim for gradual progress (0.5-2 lbs per week) rather than rapid changes. Focus on building healthy habits you can maintain long-term rather than following extreme diets.
Important Limitations
While the Mifflin-St Jeor Equation is scientifically validated and widely used, it's important to understand its limitations:
- •Estimates, Not Exact Measurements: These formulas provide estimates based on population averages. Individual metabolism can vary by 10-20% due to genetics, body composition, and other factors.
- •Activity Level is Self-Reported: People often overestimate their activity level. If you're not seeing expected results, try selecting a lower activity level.
- •Doesn't Account for Body Composition: Two people with the same weight and height can have very different calorie needs based on muscle mass. Muscle tissue burns more calories than fat tissue.
- •Medical Conditions Matter: Certain health conditions and medications can significantly affect metabolism. Examples include thyroid disorders, PCOS, diabetes, and various medications.
- •Age and Hormonal Changes: Metabolism naturally slows with age. Hormonal changes (menopause, low testosterone) can also affect calorie needs.
- •Adaptation Over Time: As you lose weight, your BMR decreases (you're moving less mass). Recalculate your calorie needs every 10-15 lbs of weight loss.
Use this calculator as a starting point, then adjust based on your real-world results over several weeks. The best calorie target is the one that produces your desired rate of weight change while allowing you to feel energized and maintain the diet long-term.
Calorie & Nutrition Tips
Evidence-based guidance for healthy nutrition and weight management
Track your food intake accurately
Use a food diary or tracking app to log everything you eat. Be honest about portion sizes and include cooking oils, sauces, and beverages. Accurate tracking is the foundation of successful calorie management.
Focus on nutrient-dense foods
Choose whole, unprocessed foods that provide more nutrients per calorie: vegetables, fruits, lean proteins, whole grains, and healthy fats. These foods keep you fuller longer and support overall health.
Don't go too low
Eating too few calories can slow your metabolism, cause muscle loss, and lead to nutritional deficiencies. Women should stay above 1,200 calories and men above 1,500 calories per day unless supervised by a healthcare provider.
Stay consistent, not perfect
Focus on hitting your calorie goal most days rather than being perfect every day. Allow flexibility for special occasions and social events. Sustainable progress beats short-term perfection.
Prioritize protein intake
Adequate protein (0.7-1g per pound of body weight) helps preserve muscle mass during weight loss, increases satiety, and has a higher thermic effect than carbs or fats. Include protein in every meal.
Combine with strength training
While you manage calories through diet, incorporate resistance training 2-3 times per week to build or maintain muscle mass. More muscle increases your BMR, making weight management easier long-term.
Frequently Asked Questions
Get answers to common questions
Still have questions?
Check our health guides or explore more calculators
Medical Disclaimer
This calorie calculator is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult with a qualified healthcare provider, registered dietitian, or nutritionist before making significant changes to your diet or starting any weight management program. This is especially important if you have existing health conditions, take medications, are pregnant or breastfeeding, or have a history of eating disorders. Your healthcare provider can assess your individual health status and provide personalized recommendations based on your specific needs and medical history.