Lion Calculator

Calorie Calculator

Estimate your daily calorie needs for weight loss, maintenance, or muscle gain using the Mifflin-St Jeor equation.

Enter your details above to see results

Calorie Calculator Methodology & Instructions

Step-By-Step Guide

  1. Enter your biological sex, age, exact height, and current weight.
  2. Select the activity level that most accurately describes your average weekly exercise and daily movement.
  3. Click calculate to determine your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE).
  4. Review the personalized caloric targets provided for weight maintenance, weight loss, or weight gain.

The Mifflin-St Jeor Equation

This calculator uses the Mifflin-St Jeor equation, introduced in 1990. It is widely considered the most reliable predictive equation for calculating resting metabolic rate in healthy adults. Once the BMR is calculated, it is multiplied by an activity factor (ranging from 1.2 for sedentary to 1.9 for extra active) to calculate Total Daily Energy Expenditure.

Mifflin-St Jeor Equation for Men:

BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5

Mifflin-St Jeor Equation for Women:

BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) - 161

Understanding Your Results

GoalCaloric AdjustmentExpected Outcome
Maintain WeightEqual to TDEEYour body weight will remain stable. This is your baseline calorie requirement.
Mild Weight Loss-250 calories/dayLoss of ~0.5 lbs (0.25 kg) per week. Ideal for highly active people or those close to their goal weight.
Standard Weight Loss-500 calories/dayLoss of ~1.0 lbs (0.45 kg) per week. The standard, sustainable rate recommended by most health professionals.
Weight Gain (Bulking)+250 to +500 calories/dayWeight gain of 0.5 to 1.0 lbs per week. When combined with resistance training, promotes muscle growth.

Frequently Asked Questions

How many calories should I eat to lose weight?
To lose weight safely, you generally need to consume 500 calories fewer than your Total Daily Energy Expenditure (TDEE). This deficit typically results in about 1 pound (0.45 kg) of weight loss per week. However, women should generally not consume fewer than 1,200 calories per day, and men should not consume fewer than 1,500 calories per day without medical supervision.
Which calorie formula is the most accurate?
The Mifflin-St Jeor equation is widely considered by clinical dietitians and the Academy of Nutrition and Dietetics to be the most accurate predictive equation for estimating Basal Metabolic Rate (BMR) in healthy adults, performing better than the older Harris-Benedict equation.
What is the difference between BMR and TDEE?
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest just to keep your organs functioning. Total Daily Energy Expenditure (TDEE) is your BMR multiplied by an activity factor, representing the total calories you burn in a day including exercise and daily movement.
Do macros matter or just total calories?
While total calories dictate whether you lose or gain weight, macronutrients (protein, carbs, fat) determine your body composition and overall health. Adequate protein preserves muscle during weight loss, while healthy fats support hormone function and carbohydrates fuel intense exercise.
Why did my weight loss stall despite eating fewer calories?
As you lose weight, your body requires fewer calories to maintain its new, smaller size. This means your BMR drops. If you don't adjust your calorie intake downward to match your new TDEE, you will hit a plateau. Metabolic adaptation and changes in daily unconscious movement (NEAT) also play a role.
Primary Reference Sources: Academy of Nutrition and Dietetics - Evidence Analysis Library, National Institutes of Health (NIH) - Calorie Count and Weight Loss
Standardized Calculation Engine · Last updated April 26, 2026

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In-Depth Analysis & Reference Guide

Total Daily Energy Expenditure (TDEE) & Caloric Balance

Achieving weight loss, muscle gain, or weight maintenance requires understanding your Total Daily Energy Expenditure (TDEE). TDEE represents the cumulative calories your body burns over 24 hours.

1. Basal Metabolic Rate (BMR) Equations

Our calculator computes BMR using the Mifflin-St Jeor equation — validated as the most accurate clinical formula for non-obese and obese individuals. BMR accounts for 60–70% of daily caloric burn, representing energy needed for organ function, circulation, and cellular repair at complete rest.

2. Activity Multipliers & Macro Allocation

BMR is multiplied by physical activity factors (Katch-McArdle multipliers from 1.2 for sedentary to 1.9 for elite physical training) to establish TDEE baseline. A caloric deficit of 500 kcal/day yields approximately 1 lb (0.45 kg) of fat loss per week without compromising lean muscle tissue when adequate protein (1.6–2.2g per kg of body weight) is maintained.