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BMR Calculator: Understanding Your Resting Metabolism

Table of Contents
  1. What is BMR?
  2. Mifflin-St Jeor Formula
  3. Factors Affecting BMR
  4. BMR vs TDEE
  5. How to Boost Your BMR

What is BMR?

Basal Metabolic Rate is the number of calories your body needs at complete rest to maintain basic life functions — breathing, circulation, cell production. BMR accounts for 60–75% of total daily calories burned.

Mifflin-St Jeor Formula

  • Men: BMR = 10 × weight(kg) + 6.25 × height(cm) – 5 × age – 161 + 166
  • Women: BMR = 10 × weight(kg) + 6.25 × height(cm) – 5 × age – 161

A 30-year-old male, 75 kg, 175 cm has a BMR of approximately 1,680 kcal/day.

Factors Affecting BMR

  • Muscle mass: More muscle = higher BMR (muscle burns 3x more calories than fat at rest)
  • Age: BMR decreases ~2% per decade after 20
  • Gender: Males typically have 5–10% higher BMR
  • Thyroid function: Hypothyroidism lowers BMR
  • Temperature: Cold environments slightly increase BMR

BMR vs TDEE

BMR = calories at rest. TDEE = BMR + exercise + daily activity + food digestion. Never eat below your BMR as it can slow metabolism and cause nutrient deficiency.

How to Boost Your BMR

  • Build lean muscle through resistance training
  • Stay hydrated — dehydration lowers metabolic rate
  • Get 7–9 hours of quality sleep
  • Eat adequate protein (thermic effect of protein is highest)
Ready to calculate? Calculate your BMR Open Calculator

Medical disclaimer: This article provides general health information and is not a substitute for professional medical advice. Consult a healthcare professional for personalized guidance.

Need a correction? Contact us if you spot an outdated rule, unclear explanation, or factual error.

Last updated: Feb 2026

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