Estimate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) to understand your calorie needs.
Your BMR & TDEE Estimate
Male
Female
Select your biological gender.
Enter your age in years.
Enter your weight in kilograms (kg).
Enter your height in centimeters (cm).
Sedentary (little to 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)
Choose the level that best describes your daily activity.
Your Results
— kcal
This is your estimated Basal Metabolic Rate (BMR), the calories your body burns at rest.
— kcal
Total Daily Energy Expenditure (TDEE)
— kcal
Target for 0.5kg/week loss
— kcal
Target for 0.5kg/week gain
Energy Expenditure Overview
BMR (Resting Calories)TDEE (Total Daily Energy Expenditure)Weight Loss Target (-500 kcal)Weight Gain Target (+500 kcal)
BMR Calculation Factors (Sample Data)
Age (Years)
Gender
Weight (kg)
Height (cm)
Calculated BMR (kcal)
Activity Factor
Estimated TDEE (kcal)
Table shows sample BMR and TDEE values based on common inputs. Actual results depend on your specific data.
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Basal Metabolic Rate, commonly known as BMR, is the minimum number of calories your body needs to perform essential functions while at rest. Think of it as the energy your body requires to keep your heart beating, lungs breathing, brain functioning, and cells repairing, even if you were to lie in bed all day without eating or moving. Understanding your BMR is a foundational step in managing your weight, optimizing your diet, and improving your overall health and fitness. This BMR weight calculator is designed to provide a quick and easy estimate of this crucial metabolic rate.
Who should use this BMR weight calculator?
Individuals aiming for weight loss, weight gain, or weight maintenance.
Athletes and fitness enthusiasts looking to fine-tune their nutrition for performance.
Anyone interested in understanding their body's basic energy needs.
People seeking to improve their understanding of metabolism and calorie balance.
Common Misconceptions about BMR:
BMR is the total calories you burn in a day: This is incorrect. BMR is just the energy expenditure at rest. Your Total Daily Energy Expenditure (TDEE) includes BMR plus the calories burned through physical activity and the thermic effect of food.
BMR is fixed and unchanging: While it's relatively stable, BMR can change over time due to factors like muscle mass, age, hormonal changes, and significant weight fluctuations.
All calculators provide the same results: Different BMR formulas exist (like Harris-Benedict, Mifflin-St Jeor, Katch-McArdle), and they can yield slightly different estimates. This calculator primarily uses the Mifflin-St Jeor equation, often considered more accurate for a general population.
{primary_keyword} Formula and Mathematical Explanation
The most widely accepted and accurate formula for estimating BMR is the Mifflin-St Jeor equation. It takes into account gender, age, weight, and height. We use this formula in our BMR weight calculator to provide a reliable estimate.
The Mifflin-St Jeor Equation
The equation differs slightly for men and women:
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, Total Daily Energy Expenditure (TDEE) is estimated by multiplying BMR by an activity factor:
TDEE = BMR × Activity Factor
Variable
Meaning
Unit
Typical Range
BMR
Basal Metabolic Rate
kcal/day
1200 – 2000+
Weight
Body weight
kg
40 – 150+
Height
Body height
cm
140 – 200+
Age
Age of the individual
Years
18 – 80+
Gender Constant (Men)
Added constant for males
kcal
+5
Gender Constant (Women)
Subtracted constant for females
kcal
-161
Activity Factor
Multiplier based on lifestyle
Unitless
1.2 (Sedentary) – 1.9 (Extra Active)
TDEE
Total Daily Energy Expenditure
kcal/day
1500 – 3000+
Practical Examples (Real-World Use Cases)
Let's see how our BMR weight calculator can be used in practice:
Example 1: Weight Loss Planning
Scenario: Sarah is a 30-year-old woman, weighing 75 kg and standing 165 cm tall. She works an office job and exercises lightly 2-3 times a week.
Inputs: Gender: Female, Age: 30, Weight: 75 kg, Height: 165 cm, Activity Level: Lightly Active (1.375)
Calculator Output:
BMR: 1488 kcal
TDEE: 2045 kcal
Target for 0.5kg/week loss: 1545 kcal
Target for 0.5kg/week gain: 2545 kcal
Interpretation: Sarah's body needs approximately 2045 calories per day to maintain her current weight with her activity level. To lose about 0.5 kg per week, she should aim for a daily intake of around 1545 kcal, creating a deficit of about 500 kcal per day.
Example 2: Muscle Gain for an Athlete
Scenario: John is a 25-year-old male athlete, weighing 85 kg and standing 180 cm tall. He trains intensely 6 days a week.
Inputs: Gender: Male, Age: 25, Weight: 85 kg, Height: 180 cm, Activity Level: Very Active (1.725)
Calculator Output:
BMR: 1891 kcal
TDEE: 3262 kcal
Target for 0.5kg/week loss: 2762 kcal
Target for 0.5kg/week gain: 3762 kcal
Interpretation: John's TDEE is around 3262 kcal. To gain muscle mass (aiming for approximately 0.5 kg per week, which requires a surplus of about 500 kcal daily), he should consume roughly 3762 calories per day. This ensures he has enough energy for his intense training and provides the building blocks for muscle growth.
How to Use This BMR Weight Calculator
Using our BMR weight calculator is straightforward. Follow these simple steps:
Select Gender: Choose 'Male' or 'Female' from the dropdown menu. This adjusts the formula slightly.
Enter Age: Input your age in years into the 'Age' field.
Enter Weight: Provide your current weight in kilograms (kg) in the 'Weight' field. Ensure accuracy for the best results.
Enter Height: Input your height in centimeters (cm) into the 'Height' field.
Choose Activity Level: Select the option that best describes your typical weekly physical activity from the 'Activity Level' dropdown. This is crucial for calculating your TDEE.
Calculate: Click the 'Calculate' button.
How to Read Your Results:
BMR (Basal Metabolic Rate): This is the primary number displayed. It represents the calories your body burns at complete rest.
TDEE (Total Daily Energy Expenditure): This is your estimated daily calorie needs, factoring in your BMR and activity level. It's the maintenance level for your current weight.
Weight Loss/Gain Targets: These show the approximate daily calorie intake needed to lose or gain about 0.5 kg per week. A deficit of 500 kcal/day generally leads to ~0.5 kg loss per week, and a surplus of 500 kcal/day leads to ~0.5 kg gain per week.
Decision-Making Guidance:
Weight Maintenance: Eat around your TDEE.
Weight Loss: Consume fewer calories than your TDEE (create a deficit).
Weight Gain: Consume more calories than your TDEE (create a surplus).
Remember, these are estimates. Monitor your progress and adjust your intake as needed. For personalized advice, consult a healthcare professional or a registered dietitian.
Key Factors That Affect BMR Results
While the Mifflin-St Jeor equation is robust, several factors can influence your actual metabolic rate, making calculator results estimates rather than exact figures:
Body Composition (Muscle vs. Fat): Muscle tissue is metabolically more active than fat tissue. Individuals with higher muscle mass generally have a higher BMR than those with the same weight but lower muscle mass. Our calculator doesn't directly measure body composition, which is a key limitation.
Age: Metabolic rate tends to decrease with age, particularly after the age of 30, often due to a natural loss of muscle mass. The formula accounts for this general trend.
Genetics: Some individuals naturally have a faster or slower metabolism due to their genetic makeup. This is a significant variable that calculators cannot quantify.
Hormonal Factors: Conditions like hypothyroidism (underactive thyroid) can significantly lower BMR, while hyperthyroidism (overactive thyroid) can increase it. Medications affecting hormones can also play a role.
Environmental Temperature: In very cold or very hot environments, your body expends extra energy to maintain its core temperature, potentially increasing BMR. However, this effect is usually minor unless exposure is extreme or prolonged.
Dietary Intake and Calorie Restriction: Severe calorie restriction or crash dieting can cause your body to adapt by slowing down your metabolism to conserve energy, thus lowering your BMR. This is a protective mechanism.
Illness, Injury, and Stress: During periods of illness, recovery from injury, or significant physical or emotional stress, your body requires more energy for repair and fighting off pathogens, which can temporarily increase BMR.
Pregnancy and Lactation: These states significantly increase a woman's metabolic needs due to the demands of fetal development and milk production. The standard BMR formulas do not apply.
Frequently Asked Questions (FAQ)
What is the difference between BMR and TDEE?BMR is the energy your body burns at complete rest, while TDEE is the total calories you burn in a day, including BMR plus all physical activities and digestion. TDEE is a more practical number for daily calorie intake planning.
Is the Mifflin-St Jeor equation the only way to calculate BMR?No, other formulas exist, such as the Harris-Benedict equation (original and revised) and the Katch-McArdle formula (which uses lean body mass). Mifflin-St Jeor is generally considered the most accurate for the general population today.
Why are my BMR results different from other online calculators?Different calculators might use different formulas (Mifflin-St Jeor vs. Harris-Benedict), slight variations in activity factor multipliers, or different units of measurement. Ensure you're inputting data consistently (e.g., kg and cm).
Can I use BMR to determine my exact calorie needs for weight loss?BMR provides a baseline. Your TDEE is a better indicator for weight management. Creating a deficit from your TDEE is key for weight loss. Remember that a 500 kcal deficit per day is an estimate for 0.5 kg loss per week; individual results can vary.
Does muscle mass affect my BMR?Yes, significantly. Muscle tissue burns more calories at rest than fat tissue. If you have a lot of muscle mass, your BMR will likely be higher than someone of the same weight and height with less muscle.
What does a "sedentary" activity level mean?A sedentary lifestyle typically involves sitting or lying down for most of the day, with very little or no physical activity or exercise. Desk jobs often fall into this category.
How often should I recalculate my BMR?It's advisable to recalculate your BMR and TDEE periodically, especially if there have been significant changes in your weight, body composition (e.g., after starting a new fitness routine), or age. Every 6-12 months is a good general guideline unless major changes occur.
Can this calculator predict weight loss speed?This calculator provides an *estimated* calorie target for a specific rate of weight loss (0.5 kg/week). Actual weight loss speed depends on many factors, including adherence to the calorie target, metabolic adaptations, water retention, and exercise consistency.
Related Tools and Internal Resources
BMR Weight CalculatorOur primary tool to estimate your basal metabolic rate and daily calorie needs.
BMR Formula ExplainedDeep dive into the science behind BMR calculations, including the Mifflin-St Jeor equation.
BMI CalculatorCalculate your Body Mass Index (BMI) to assess your weight category relative to your height. A complementary metric for health assessment.
Calorie Deficit CalculatorDetermine the precise calorie deficit needed for your specific weight loss goals over a set period.
Macronutrient CalculatorCalculate the ideal breakdown of protein, carbohydrates, and fats for your diet based on your goals.
Water Intake CalculatorEstimate your daily recommended water consumption based on factors like weight, activity, and climate.
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var weight = parseFloat(document.getElementById("weight").value);
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if (gender === "male") {
bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5;
} else { // female
bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161;
}
var tdee = bmr * activityLevel;
var weightLossTarget = tdee – 500; // Target for ~0.5kg loss per week
var weightGainTarget = tdee + 500; // Target for ~0.5kg gain per week
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document.getElementById("tdeeResult").textContent = Math.round(tdee) + " kcal";
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var weightGainTarget = document.getElementById("weightGainTarget").textContent;
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resultsText += "- Weight: " + weight + " kg\n";
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resultsText += "- Target for ~0.5kg/week gain: " + weightGainTarget + "\n\n";
resultsText += "Assumptions:\n";
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datasets: [{
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