Calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) to determine the exact calorie deficit needed for your weight loss goals.
Sedentary (office job, little exercise)
Lightly Active (exercise 1-3 days/week)
Moderately Active (exercise 3-5 days/week)
Very Active (exercise 6-7 days/week)
Extra Active (physical job + exercise)
Please enter valid numbers for all fields.
Basal Metabolic Rate
0
Calories burned at complete rest
Maintenance Calories (TDEE)
0
Calories to maintain current weight
Weight Loss Plan
To lose weight, you must consume fewer calories than your TDEE. Below are recommended daily calorie targets based on your activity level.
Goal Intensity
Calorie Deficit
Daily Calories
Est. Loss/Week
Mild Weight Loss
-250 cal
0
0.5 lbs (0.23 kg)
Moderate Weight Loss
-500 cal
0
1.0 lbs (0.45 kg)
Extreme Weight Loss
-1000 cal
0
2.0 lbs (0.91 kg)
*Do not go below 1200 calories (women) or 1500 calories (men) per day without medical supervision.
Understanding Your BMR and Weight Loss
Successful weight loss boils down to energy balance: calories in versus calories out. Your Basal Metabolic Rate (BMR) is the foundational number in this equation. It represents the number of calories your body burns just to perform basic life-sustaining functions like breathing, circulation, and cell production.
How This Calculator Works
This calculator uses the Mifflin-St Jeor Equation, widely considered by dietitians and health professionals to be the most accurate standard for calculating BMR. Once your BMR is established, we apply an activity multiplier to determine your Total Daily Energy Expenditure (TDEE).
BMR: Your "coma calories" – what you'd burn lying in bed all day.
TDEE: Your real-world burn rate, including walking, working, and exercise.
Using Your Results for Weight Loss
To lose fat, you need a calorie deficit. We have provided three tiers of deficits:
Mild (-250 cal): Slow and sustainable. Best for people who are already lean or want to preserve maximum muscle mass.
Moderate (-500 cal): The gold standard. This typically results in 1 lb of fat loss per week and is manageable for most people.
Extreme (-1000 cal): Aggressive. This should generally only be attempted by individuals with higher body fat percentages or for short periods under supervision.
Frequently Asked Questions
Does BMR change as I lose weight?
Yes. As you lose weight, your body requires less energy to move and function. This is often why weight loss plateaus occur. You should recalculate your BMR for every 10-15 lbs (5-7 kg) lost to adjust your calorie intake targets.
Should I eat below my BMR to lose weight faster?
Generally, no. Eating below your BMR can trigger metabolic adaptation, where your body aggressively slows down energy expenditure to "survive." It can also lead to nutrient deficiencies, muscle loss, and fatigue. It is safer to create a deficit from your TDEE, not your BMR.
How accurate is the Mifflin-St Jeor equation?
Studies show it is usually accurate within 10% for most people. However, factors like muscle mass, hormonal health (e.g., thyroid issues), and genetics can influence your actual metabolic rate. Use these numbers as a starting point and adjust based on your real-world progress over 2-3 weeks.
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document.getElementById('error-msg').style.display = 'none';
// 1. Get Inputs
var age = parseFloat(document.getElementById('age').value);
var gender = document.querySelector('input[name="gender"]:checked').value;
var activity = parseFloat(document.getElementById('activity').value);
var weight, height;
// 2. Handle Units & Validation
if (currentUnit === 'metric') {
weight = parseFloat(document.getElementById('weight-kg').value);
height = parseFloat(document.getElementById('height-cm').value);
} else {
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var heightFt = parseFloat(document.getElementById('height-ft').value);
var heightIn = parseFloat(document.getElementById('height-in').value);
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// Men: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
// Women: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
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// 4. Calculate TDEE
var tdee = bmr * activity;
// 5. Calculate Deficits
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var moderateLoss = tdee – 500;
var extremeLoss = tdee – 1000;
// Safety check: don't recommend dangerously low calories
var minCalories = (gender === 'male') ? 1500 : 1200;
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