What is the difference between BMR and TDEE?

BMR is the calories burned at complete rest. TDEE (Total Daily Energy Expenditure) includes BMR plus all daily activities—from walking around to exercise. TDEE is typically 1.2-2x your BMR depending on activity level.

Should I eat below my BMR to lose weight?

No. Eating below BMR for extended periods can slow metabolism, cause muscle loss, and create nutritional deficiencies. For healthy weight loss, eat above BMR but below TDEE—typically a 500-calorie deficit from TDEE.

Why does BMR decrease with age?

Age-related BMR decline is primarily due to muscle loss (sarcopenia), hormonal changes, and reduced cellular activity. Resistance training and adequate protein can help preserve muscle and maintain higher BMR.

How accurate is the Mifflin-St Jeor equation?

It's accurate within about 10% for most people. Factors like muscle mass, genetics, and hormonal conditions can cause individual variation. For precise measurement, indirect calorimetry testing is available at some clinics.

Can I increase my BMR?

Yes, primarily through building muscle mass with resistance training. Each pound of muscle burns about 6 calories per day at rest, compared to 2 calories for fat. Adequate sleep and avoiding extreme calorie restriction also support healthy BMR.

Why do men have higher BMR than women?

Men typically have more muscle mass and less body fat than women of similar weight, and testosterone promotes higher metabolic rate. This translates to roughly 5-10% higher BMR for men on average.

BMR Calculator — Calories Burned Doing Nothing (2026)

Calculate your daily BMR — calories burned doing absolutely nothing. Free Mifflin-St Jeor calculator with weight, age, and sex inputs.

Loading the interactive calculator… If it doesn't appear, visit the homepage.