Definition: What is BMR?
Basal Metabolic Rate (BMR) represents the energy cost of keeping your body alive at total rest. It is often referred to as "Coma Calories" — the energy your body would burn if you did nothing but sleep all day. This is distinct from RMR (Resting Metabolic Rate), which is slightly higher as it includes energy for digestion and small movements.
The Formulas (Mifflin vs. Harris-Benedict)
There are two primary equations used in clinical settings. This calculator defaults to the Mifflin-St Jeor equation, which studies have shown to be more accurate for modern populations.
Mifflin-St Jeor (2025 Standard):
Men: (10 × weight kg) + (6.25 × height cm) - (5 × age) + 5
Women: (10 × weight kg) + (6.25 × height cm) - (5 × age) - 161
Harris-Benedict (1918 Original):
Often overestimates caloric needs by ~5%.
Calculation Example (Step-by-Step)
Scenario: 31-year-old female
Height: 168 cm | Weight: 65 kg
Formula: (10 × 65) + (6.25 × 168) - (5 × 31) - 161
Step 1: 650 + 1,050 - 155 - 161
Result: 1,384 kcal/day
This means her body burns 1,384 calories every day just to stay alive, before any movement.
Frequently Asked Questions
Do I burn calories when sleeping?
Why is my BMR lower than the calculator says?
How do I calculate BMR for a 40-year-old woman?
Does thyroid function affect BMR?
Tools & Data Verified by the EverydayCalculators Medical Research Team.
Last updated: December 2026.