1. Basal Metabolic Rate (BMR): "+Math.round(bmr)+" kcal
2. Activity Multiplier: x"+activity+"
3. Total Daily Energy Expenditure (TDEE): "+Math.round(tdee)+" kcal";document.getElementById('stepDetails').innerHTML=detailHtml;document.getElementById('stepDetails').style.display='block';}else{document.getElementById('stepDetails').style.display='none';}}
Using the Calorie Intake Calculator
The calorie intake calculator is an essential tool for anyone looking to manage their body weight effectively. Whether your goal is to lose fat, build muscle, or maintain your current physique, knowing your daily energy expenditure is the first step toward success. This calculator uses the Mifflin-St Jeor equation, widely regarded as the most accurate standard for healthy individuals.
By providing your age, weight, height, and activity level, you can generate a personalized roadmap for your nutrition. The results provide three distinct targets based on standard health recommendations.
- Age
- Your metabolic rate naturally slows down as you age due to changes in hormonal profile and muscle mass loss.
- Weight and Height
- Larger bodies require more energy to function, both at rest and during physical movement.
- Activity Level
- This factor accounts for non-exercise thermogenesis (NEAT) and purposeful exercise, significantly impacting your total daily needs.
How It Works: The Mifflin-St Jeor Formula
To find your daily needs, the calorie intake calculator first determines your Basal Metabolic Rate (BMR)—the energy your body burns just to keep your organs functioning while at rest. The formula used is:
Men: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
Women: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
- TDEE Calculation: Once the BMR is established, it is multiplied by an activity factor (1.2 to 1.9) to find your Total Daily Energy Expenditure (TDEE).
- Deficit for Weight Loss: To lose approximately 0.5 kg (1 lb) per week, a deficit of 500 calories per day is typically recommended.
- Surplus for Weight Gain: To gain approximately 0.5 kg (1 lb) per week, a surplus of 500 calories per day is added to the maintenance total.
Calculation Example
Example: A 25-year-old male, weighing 85 kg and 180 cm tall, with a moderately active lifestyle (3-5 days of exercise).
Step-by-step solution:
- BMR = (10 × 85) + (6.25 × 180) – (5 × 25) + 5 = 850 + 1125 – 125 + 5 = 1,855 kcal
- Activity Multiplier (Moderately Active) = 1.55
- TDEE (Maintenance) = 1,855 × 1.55 = 2,875 kcal
- Weight Loss Target = 2,875 – 500 = 2,375 kcal per day
- Weight Gain Target = 2,875 + 500 = 3,375 kcal per day
Common Questions
How accurate is this calorie intake calculator?
While the Mifflin-St Jeor equation is highly accurate for most people, it does not account for body composition (muscle mass vs. fat mass). Individuals with very high muscle mass may find the calculator underestimates their needs, while those with very high body fat percentages might find it slightly overestimates.
What is a "safe" calorie deficit?
Generally, a deficit of 500 to 750 calories per day is considered safe and sustainable for most people. It is generally advised not to drop below 1,200 calories per day for women or 1,500 calories per day for men without medical supervision to ensure adequate nutrient intake.
Does the calculator account for exercise?
Yes, by selecting your activity level. If you select "Moderately Active," the calculator assumes you are already exercising regularly. You should not "eat back" the calories burned during those workouts, as they are already factored into your daily total.