BMR Calculator (Mifflin-St Jeor Formula) — GoDietPlan
Metabolic Calculation Engine

Basal Metabolic Rate (BMR) Calculator

Calculate the exact baseline calories your body expends every 24 hours at rest using the validated Mifflin-St Jeor Equation. Read our full formula breakdown on our Calculation Methodology page.

Measurement System
Your Estimated Basal Metabolic Rate
1,699calories / day

This is the exact number of calories your organs, brain, and tissues consume in a 24-hour coma state at rest.

Estimated Daily Burn by Physical Activity (TDEE)

Multiply your BMR by your physical activity factor to find your total daily calorie maintenance:

Activity TierMultiplierLifestyle RoutineDaily Calories
Sedentary1.2xDesk job, little or no exercise2,039 kcal
Lightly Active1.375xLight exercise 1–3 days/week2,336 kcal
Moderately Active1.55xModerate exercise 3–5 days/week2,633 kcal
Very Active1.725xHard exercise 6–7 days/week2,931 kcal
Extremely Active1.9xPhysical job or 2x daily training3,228 kcal

Equation Comparison for Your Profile

Mifflin-St Jeor (Standard)
1,699 kcal

Recommended by the Academy of Nutrition & Dietetics.

Harris-Benedict (Revised 1984)
1,763 kcal

Older formula; tends to slightly overestimate energy expenditure.

Frequently Asked Questions

Should I eat below my BMR to lose weight faster?

Generally no. Eating significantly below your BMR triggers heavy physiological compensations, including rapid down-regulation of active thyroid hormones (T3), increased muscle protein catabolism, and sudden drops in spontaneous daily movement (NEAT). A safe deficit is calculated by subtracting 15–20% from your TDEE, not your BMR.

What is the difference between BMR and RMR?

Basal Metabolic Rate (BMR) represents baseline energy expenditure under strict laboratory conditions (overnight rest, 12 hours of fasting, and minimal movement upon waking). Resting Metabolic Rate (RMR) measures resting burn in less restrictive conditions and is typically 5% to 10% higher than BMR.

Calculation Disclaimer: For informational and planning estimates only; not medical advice. Consult a healthcare professional before making major dietary changes. Read our full Medical Disclaimer and Calculation Methodology.

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