Professional Basal Metabolic Rate & TDEE Calculator
BMR & Calorie Deficit Calculator
Calculate your daily energy needs and weight loss targets instantly.
Enter your age in years.
Please enter a valid age (15-100).
Enter height in centimeters.
Enter weight in kilograms.
Enter height in feet and inches.
Enter weight in pounds.
Sedentary (little or no exercise)
Lightly Active (exercise 1-3 days/week)
Moderately Active (exercise 3-5 days/week)
Very Active (exercise 6-7 days/week)
Super Active (physical job or 2x training)
Select the option that best matches your weekly routine.
Your Basal Metabolic Rate (BMR)
1,780 kcal
Calories burned at complete rest
Maintenance (TDEE)
2,448 kcal
Mild Weight Loss
2,198 kcal
Moderate Weight Loss
1,948 kcal
Calorie Deficit Breakdown
Goal
Daily Calories
Weekly Deficit
Est. Weekly Loss
*Estimated weight loss assumes 3,500 kcal deficit equals approx 1 lb (0.45 kg) of fat loss.
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What is "How Do I Calculate My BMR for Weight Loss"?
When asking "how do i calculate my bmr for weight loss," you are essentially looking for the mathematical foundation of your metabolism. BMR stands for Basal Metabolic Rate. It represents the number of calories your body requires to perform basic life-sustaining functions—such as breathing, circulation, nutrient processing, and cell production—while you are at complete rest.
Understanding your BMR is the critical first step in any weight management plan. It serves as the baseline for calculating your Total Daily Energy Expenditure (TDEE), which is the total number of calories you burn in a day when activity is added. By knowing these numbers, you can scientifically determine the calorie intake required to create a deficit for weight loss, rather than guessing.
This metric is useful for anyone from elite athletes to individuals just starting their fitness journey. A common misconception is that exercise burns the majority of your daily calories; in reality, your BMR accounts for 60-75% of your total daily energy burn.
BMR Formula and Mathematical Explanation
To answer "how do i calculate my bmr for weight loss" accurately, we use the Mifflin-St Jeor Equation. This formula is widely considered by the Academy of Nutrition and Dietetics to be the most accurate for the general population.
The Mifflin-St Jeor Equation
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
Variable Definitions
Variable
Meaning
Unit
Typical Range
Weight (W)
Total body mass
kg
40 – 150+ kg
Height (H)
Vertical stature
cm
140 – 210 cm
Age (A)
Chronological age
years
18 – 80+ years
Constant
Gender adjustment
N/A
+5 (Men), -161 (Women)
Practical Examples (Real-World Use Cases)
Example 1: Moderate Weight Loss Goal
Scenario: Sarah is a 35-year-old female, 165 cm tall, weighing 75 kg. She works an office job but goes to the gym 3 times a week (Moderately Active).
Weight Loss Target: For a moderate deficit of 500 kcal, his target is 1,786 kcal.
Analysis: Even though John is heavier, his sedentary lifestyle limits his TDEE. He must focus on diet to lose weight effectively.
How to Use This BMR Calculator
Follow these steps to effectively determine how do i calculate my bmr for weight loss using the tool above:
Select Unit System: Choose Metric (kg/cm) or Imperial (lbs/ft) based on your preference.
Enter Personal Details: Input your gender, age, current weight, and height accurately. Small variances can affect the result.
Choose Activity Level: Be honest about your activity. "Lightly Active" usually means walking or light exercise 1-3 days a week. Overestimating activity is a common error that leads to overeating.
Review Results:
BMR: Your coma calories (don't eat below this long-term without medical supervision).
Maintenance (TDEE): What you eat to stay the same weight.
Weight Loss Targets: Choose "Mild" for sustainable loss or "Moderate" for faster results.
Key Factors That Affect BMR Results
Several biological and environmental factors influence the answer to "how do i calculate my bmr for weight loss":
Muscle Mass: Muscle tissue burns more calories at rest than fat tissue. Two people of the same weight can have drastically different BMRs if one has higher muscle mass.
Age: Metabolism generally slows down by about 2-3% per decade after age 20, primarily due to loss of muscle mass and hormonal changes.
Gender: Men typically have a higher BMR than women because they tend to have more lean muscle mass and larger organs relative to their size.
Genetics: Some individuals naturally have a faster or slower metabolic rate, though this variance is usually smaller than people assume (often within 10-15%).
Hormonal Health: Conditions like hypothyroidism or Cushing's syndrome can significantly lower BMR, making weight loss more difficult.
Diet History: Chronic crash dieting can lower BMR as the body adapts to conserve energy (often called "starvation mode"), reducing the calories burned at rest.
Frequently Asked Questions (FAQ)
Can I eat below my BMR to lose weight faster?
It is generally not recommended to eat below your BMR for extended periods. Doing so can trigger muscle loss, nutrient deficiencies, and metabolic adaptation, where your body slows down calorie burning to survive.
How often should I recalculate my BMR?
You should recalculate your BMR every time you lose 5-10 lbs (2-5 kg). As you lose weight, your body requires less energy to function, meaning your BMR and TDEE decrease.
Does the calculator account for muscle mass?
The Mifflin-St Jeor equation uses total body weight. If you are very muscular, this calculator may underestimate your BMR. In that case, the Katch-McArdle formula (which uses body fat percentage) might be more accurate.
Why is my weight loss stalling even though I'm in a deficit?
This could be due to water retention, metabolic adaptation, or tracking errors. Ensure you are weighing food accurately and recalculate your BMR for your new, lower weight.
Does sleep affect my BMR?
Indirectly, yes. Poor sleep disrupts hormones like ghrelin and leptin, which control hunger, and can lead to muscle loss, which eventually lowers BMR.
Is BMR the same as RMR?
They are similar but not identical. BMR (Basal Metabolic Rate) is measured under strict laboratory conditions. RMR (Resting Metabolic Rate) is less strict and is usually about 10% higher than BMR. For weight loss purposes, they are often used interchangeably.
How accurate are online BMR calculators?
They provide a solid estimate, usually within 10% of your actual metabolic rate. They are excellent starting points for determining "how do i calculate my bmr for weight loss" but should be adjusted based on real-world progress.
Does eating more frequently boost BMR?
The "thermic effect of food" exists, but meal frequency has a negligible effect on total daily BMR. Total calorie intake vs. expenditure is the primary driver of weight loss.
Related Tools and Internal Resources
Explore more tools to help you manage your health and finances:
TDEE Calculator – Calculate your Total Daily Energy Expenditure including exercise.