Basal Metabolic Rate (BMR) Calculator
Your Results
Calories burned at complete rest 0 kcal
Calories needed to maintain current weight 0 kcal
NHS Weight Loss Guidance: To lose weight safely (approx 0.5kg to 1kg per week), the NHS typically recommends creating a deficit of 500-600 calories from your maintenance amount.
Understanding Basal Metabolic Rate (BMR)
Your Basal Metabolic Rate (BMR) represents the minimum amount of energy (measured in calories) your body requires to perform basic life-sustaining functions while at rest. These functions include breathing, circulating blood, controlling body temperature, cell growth, and brain and nerve function.
Even if you stayed in bed all day without moving, your body would still burn calories. This accounts for approximately 60% to 75% of the total calories you burn every day. The calculator above uses the Mifflin-St Jeor equation, which is widely recognized by health professionals and is often aligned with NHS standards for accuracy in estimating energy requirements.
How BMR Differs from TDEE
While BMR is your baseline, your Total Daily Energy Expenditure (TDEE) adds the calories burned through physical activity and the digestion of food. This is often referred to as your "maintenance calories."
- BMR: Coma-state calories.
- NEAT (Non-Exercise Activity Thermogenesis): Fidgeting, walking, typing.
- EAT (Exercise Activity Thermogenesis): Planned sports and gym sessions.
- TEF (Thermic Effect of Food): Energy used to digest food.
NHS Recommendations for a Healthy Metabolism
According to NHS guidelines, the average man needs around 2,500kcal (10,500kJ) a day to maintain his weight, while the average woman needs around 2,000kcal (8,400kJ). However, these are broad averages. Calculating your specific BMR provides a more personalized baseline.
To support a healthy metabolic rate:
- Build Muscle: Muscle tissue burns more calories at rest than fat tissue. Strength training is highly recommended.
- Eat Protein: Protein has a higher thermic effect than fats or carbohydrates, meaning your body uses more energy to digest it.
- Stay Active: While you cannot drastically change your BMR immediately, increasing your overall activity level helps manage weight effectively.
- Avoid Crash Diets: Drastically reducing calorie intake (e.g., below 1,200 for women or 1,500 for men) can signal the body to slow down its metabolism to conserve energy.
The Calculation Formula
This tool utilizes the Mifflin-St Jeor Equation, widely considered the most reliable formula for the general population:
- Men: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
- Women: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
This base number is then multiplied by an activity factor ranging from 1.2 (sedentary) to 1.9 (extremely active) to determine your daily maintenance calories.