Understand your body's energy needs to create an effective weight loss plan. Our BMR calculator helps you determine your resting calorie burn.
BMR Calculator for Weight Loss
Male
Female
Select your biological sex for accurate calculation.
Enter your current age in whole years.
Enter your current weight in kilograms.
Enter your height in centimeters.
Sedentary (little or no exercise)
Lightly Active (light exercise/sports 1-3 days/week)
Moderately Active (moderate exercise/sports 3-5 days/week)
Very Active (hard exercise/sports 6-7 days a week)
Extra Active (very hard exercise/sports & physical job or 2x training)
Choose the option that best describes your daily physical activity.
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Your Results
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Formula Used:
We use the Mifflin-St Jeor equation to estimate your Basal Metabolic Rate (BMR), the calories your body burns at rest. For total daily energy expenditure (TDEE), we multiply BMR by your selected activity factor.
Mifflin-St Jeor Equation:
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
TDEE = BMR × Activity Factor
BMR: — kcal/day
TDEE: — kcal/day
Estimated Weight Loss Calories: — kcal/day
Key Assumptions for Weight Loss
Calorie Deficit Target: — kcal/day
Estimated Weekly Fat Loss: — kg
Your Basal Metabolic Rate (BMR): — kcal/day
What is BMR for Weight Loss?
{primary_keyword} refers to the minimum number of calories your body needs to perform essential life-sustaining functions while at complete rest. These functions include breathing, circulating blood, maintaining body temperature, and cell production. Understanding your BMR is a cornerstone of any successful weight loss strategy because it provides a baseline for your body's energy expenditure. Without knowing how many calories you burn at rest, it's difficult to accurately determine how many calories you need to consume to create a deficit for weight loss.
Who should use it? Anyone looking to lose weight, gain muscle, or simply maintain their current weight can benefit from knowing their BMR. It's particularly crucial for weight loss as it helps in setting realistic calorie intake goals. By understanding your BMR, you can ensure you're not undereating to the point of harming your metabolism or overeating and hindering your progress.
Common misconceptions about BMR include thinking it's the total calories you burn in a day (it's not; that's TDEE) or believing it's fixed and unchangeable (your BMR can be influenced by factors like muscle mass, age, and metabolism). Another misconception is that a very low-calorie diet is always best; this can actually lower your BMR over time, making weight loss harder.
BMR Formula and Mathematical Explanation
The most widely accepted formula for calculating BMR is the Mifflin-St Jeor equation. It's considered more accurate than older formulas like the Harris-Benedict equation, especially for modern populations. Our calculator uses this equation, which accounts for age, sex, weight, and height.
The Mifflin-St Jeor Equation:
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
Once BMR is calculated, we estimate the Total Daily Energy Expenditure (TDEE) by multiplying the BMR by an activity factor. TDEE represents the total calories burned in a day, including all activities. For weight loss, a common approach is to consume 500-1000 calories less than your TDEE per day, aiming for a loss of approximately 0.5 to 1 kg (1-2 lbs) per week.
Interpretation: Sarah needs approximately 2279 calories to maintain her current weight. To lose about 0.45 kg per week, she should aim to consume around 1779 calories daily. This is a sustainable rate of weight loss.
Interpretation: Mark's TDEE is about 2516 calories. A 1000-calorie deficit would put his target intake at roughly 1516 calories. This aggressive deficit targets nearly 1 kg of fat loss per week. While effective, Mark should monitor his energy levels and ensure he's meeting nutritional needs.
How to Use This BMR Calculator for Weight Loss
Using our calculator is straightforward. Follow these steps:
Select Biological Sex: Choose 'Male' or 'Female'.
Enter Age: Input your age in years.
Enter Weight: Provide your current weight in kilograms.
Enter Height: Input your height in centimeters.
Choose Activity Level: Select the option that best reflects your typical daily physical activity. Be honest for the most accurate results.
Click Calculate: Press the "Calculate BMR & TDEE" button.
Reading Your Results:
BMR: This is the number of calories your body burns at rest.
TDEE: This is your total estimated daily calorie burn, factoring in your activity level.
Estimated Weight Loss Calories: This suggests a daily calorie intake for a specific weight loss rate (defaulting to a 500 kcal deficit).
Calorie Deficit Target: The number of calories you are aiming to subtract from your TDEE.
Estimated Weekly Fat Loss: An approximation of how much fat you could lose per week based on your calorie deficit. (Note: 1 kg of fat ≈ 7700 kcal).
Decision-Making Guidance: Aim for a calorie deficit that is sustainable and aligns with your health goals. A deficit of 500-1000 calories per day is generally recommended for safe and effective weight loss. Consult with a healthcare professional or registered dietitian if you have underlying health conditions or specific dietary needs.
Key Factors That Affect BMR Results
While the Mifflin-St Jeor equation provides a good estimate, several factors can influence your actual metabolic rate:
Body Composition (Muscle vs. Fat): Muscle tissue burns more calories at rest than fat tissue. Individuals with higher muscle mass will have a higher BMR, even at the same weight. Building muscle through resistance training can increase your BMR over time.
Age: BMR naturally declines with age, primarily due to a gradual loss of muscle mass and hormonal changes.
Genetics: Your inherited genes play a role in determining your metabolic rate. Some people are naturally predisposed to have a faster metabolism.
Hormonal Factors: Conditions like thyroid disorders (hypothyroidism or hyperthyroidism) can significantly impact BMR. An underactive thyroid lowers BMR, while an overactive thyroid raises it.
Dietary Intake and Previous Dieting: Severe calorie restriction over long periods can cause your body to adapt by lowering your BMR (adaptive thermogenesis) to conserve energy. This is why crash dieting can be counterproductive.
Environmental Temperature: Your body expends energy to maintain its core temperature. In very cold or very hot environments, your BMR might slightly increase as your body works harder to regulate temperature.
Health Status: Illness, fever, or injury can temporarily increase BMR as the body works to heal and fight off infection.
Frequently Asked Questions (FAQ)
Is the Mifflin-St Jeor equation the best for everyone?
It's generally considered one of the most accurate for the general adult population. However, individual variations exist, and factors like extreme body composition or specific medical conditions might require personalized assessments.
Can I use my weight in pounds and height in feet/inches?
Our calculator requires weight in kilograms and height in centimeters for accuracy. You can use online converters if needed (e.g., 1 kg = 2.20462 lbs, 1 inch = 2.54 cm).
What if my calculated TDEE is very low?
A low TDEE might indicate a smaller body size, lower muscle mass, or a more sedentary lifestyle. If it falls below 1200 calories (for women) or 1500 calories (for men), it's crucial to consult a professional to ensure adequate nutrient intake and avoid potential metabolic slowdown.
How much weight can I realistically expect to lose per week?
A safe and sustainable rate is typically 0.5 to 1 kg (1 to 2 lbs) per week. This corresponds to a daily deficit of 500 to 1000 calories. Faster loss is possible but may be less sustainable and could lead to muscle loss.
Does this calculator account for exercise calories burned?
The calculator estimates TDEE based on your *activity level* (how active you are generally). Calories burned during specific workouts are in addition to this and can be factored in separately if you wish to create a larger deficit, but be careful not to over-estimate exercise calorie burn.
What happens to my BMR if I lose weight?
As you lose weight, particularly fat mass, your BMR will likely decrease slightly because there's less body mass to sustain. This is why weight loss can sometimes slow down, and adjustments to calorie intake or activity may be needed.
Is it okay to eat below my BMR?
Eating below your BMR for extended periods is generally not recommended. It can lead to nutrient deficiencies, muscle loss, fatigue, and a significant drop in your metabolic rate, making future weight loss more challenging.
How often should I recalculate my BMR?
It's a good idea to recalculate your BMR every few months, especially after significant changes in weight, body composition, or activity level, or as you age.