BMR Calculator

Basal metabolic rate — calories burned at complete rest.

Overview

Measures Basal Metabolic Rate (BMR)—the baseline number of calories your body burns at complete physical and digestive rest to maintain vital life functions.

Formula & Calculation Method

BMR (Mifflin-St Jeor) = (10 × W) + (6.25 × H) - (5 × A) + s

Calculated using the clinically validated Mifflin-St Jeor equation. W = Weight (kg), H = Height (cm), A = Age (years), s = Sex factor (+5 for men, -161 for women).

Worked Example: 30-Year-Old Female Weighing 62 kg at 165 cm

Inputs: Age = 30 | Sex = Female | Weight = 62 kg | Height = 165 cm

  • Weight component = 10 × 62 = 620
  • Height component = 6.25 × 165 = 1,031.25
  • Age component = 5 × 30 = 150
  • Female constant = -161
  • BMR = 620 + 1,031.25 - 150 - 161 = 1,340.25 kcal/day

Summary: Age = 30 | Sex = Female | Basal Metabolic Rate = 1,340 kcal/day

Common Use Cases

  • Calorie Floor Determination: Identify the minimum caloric threshold below which diets risk metabolic suppression.
  • Body Recomposition: Track how adding lean skeletal muscle tissue increases resting basal metabolic rate.
  • Clinical Nutrition: Provide baseline energy expenditure estimates for hospital patients and post-operative recovery.

Frequently Asked Questions

Can I eat below my BMR to lose weight faster?

Consistently eating below your BMR causes fatigue, muscle loss, nutrient deficiencies, and hormonal imbalances; create your deficit from your TDEE, not your BMR.

How can I naturally increase my BMR?

Building skeletal muscle tissue via resistance strength training increases resting metabolic rate, as muscle burns more calories at rest than fat tissue.

Does BMR decrease with age?

Yes, BMR typically declines by roughly 1% to 2% per decade after age 30, primarily due to gradual loss of lean muscle mass (sarcopenia).

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