BMR Calculator - Calculate Your Basal Metabolic Rate Free BMR Calculator
Use our free BMR calculator to estimate your Basal Metabolic Rate. Enter your age, gender, height and weight to find out how many calories your body burns at rest using both the Mifflin-St Jeor and Harris-Benedict equations.
Your Details
Your Results
Daily Calorie Needs by Activity Level
| Activity Level | Factor | Calories/Day |
|---|---|---|
| Sedentary | 1.20 | 0 |
| Lightly Active | 1.375 | 0 |
| Moderately Active | 1.55 | 0 |
| Very Active | 1.725 | 0 |
| Extra Active | 1.90 | 0 |
BMR Calculator - Guide
What is BMR?
BMR (Basal Metabolic Rate) is the number of calories your body needs to sustain basic life functions at complete rest — breathing, circulation, cell production, and nutrient processing. It represents the minimum energy expenditure needed to keep you alive if you did nothing all day.
BMR typically accounts for 60–75% of your total daily calorie expenditure, making it the single largest component of your energy needs.
BMR Formulas
Mifflin-St Jeor Equation (Recommended):
Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
Harris-Benedict Equation (Revised):
Men: BMR = 13.397 × weight(kg) + 4.799 × height(cm) − 5.677 × age + 88.362
Women: BMR = 9.247 × weight(kg) + 3.098 × height(cm) − 4.330 × age + 447.593
TDEE = BMR × Activity Factor
Activity Level Multipliers
- 1.2 — Sedentary (desk job, little or no exercise)
- 1.375 — Lightly active (light exercise 1–3 days/week)
- 1.55 — Moderately active (moderate exercise 3–5 days/week)
- 1.725 — Very active (hard exercise 6–7 days/week)
- 1.9 — Extra active (very hard daily exercise or physical job)
Understanding Your Results
- BMR: Calories your body burns at complete rest. You should never eat below this number.
- TDEE: Total calories burned per day including activity. Eating this amount maintains your current weight.
- Weight Loss: Eating 250–500 fewer calories than TDEE creates a sustainable deficit for gradual fat loss.
- Weight Gain: Eating 250–500 more calories than TDEE creates a surplus for muscle building.
Factors That Affect BMR
- Age: BMR decreases roughly 1–2% per decade after age 20.
- Gender: Men generally have a higher BMR due to greater muscle mass.
- Body Composition: More muscle mass = higher BMR. Strength training can increase your resting metabolism.
- Genetics: Metabolic rate can vary 200–300 cal/day between individuals of the same size.
- Diet: Very low-calorie diets can reduce BMR by 20% or more (adaptive thermogenesis).
- Temperature: Exposure to cold temperatures can temporarily increase BMR.
Tips for a Healthy Metabolism
- Build Muscle: Resistance training increases lean mass, which raises your BMR.
- Don’t Starve: Eating below your BMR slows metabolism. Aim for a moderate calorie deficit.
- Stay Active: Regular exercise boosts both BMR and TDEE.
- Stay Hydrated: Drinking cold water can temporarily increase metabolic rate by 10–30%.
- Sleep Well: Poor sleep reduces metabolic rate and increases hunger hormones.
- Eat Protein: Protein has a higher thermic effect (20–30%) compared to carbs (5–10%) and fats (0–3%).