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A BMR Calculator estimates your Basal Metabolic Rate, which is the number of calories your body burns each day while at rest to maintain vital functions like breathing, circulation, and cell production.
Knowing your BMR helps you understand how many calories your body needs for survival—and it’s the foundation for calculating your TDEE (Total Daily Energy Expenditure), which is used for weight loss, maintenance, or gain.
CalcNest’s BMR Calculator uses medically approved formulas like Mifflin-St Jeor and Harris-Benedict equations for accurate, personalized results.
Enter the following information:
Age – In years
Gender – Male or female
Weight – In kilograms or pounds
Height – In centimeters or feet/inches
Formula (optional) – Choose between Mifflin-St Jeor or Harris-Benedict
Once entered, the tool calculates your BMR in calories/day, which reflects the minimum number of calories your body needs at rest.
Accurate results using trusted BMR formulas
Supports both metric and imperial units
Instant calculation, 100% free
Works for all age groups and body types
No login or registration required
Mobile-optimized and easy to use
Age: 30
Gender: Female
Height: 165 cm
Weight: 65 kg
Formula: Mifflin-St Jeor
Result:
BMR = 1,383 calories/day
This is the number of calories her body needs at rest.
For men: BMR = 10 × weight (kg) + 6.25 × height (cm) – 5 × age + 5
For women: BMR = 10 × weight (kg) + 6.25 × height (cm) – 5 × age – 161
For men: BMR = 66.5 + (13.75 × weight) + (5.003 × height) – (6.75 × age)
For women: BMR = 655.1 + (9.563 × weight) + (1.850 × height) – (4.676 × age)
Once you know your BMR, you can calculate your TDEE based on your activity level:
| Activity Level | TDEE Multiplier |
|---|---|
| Sedentary (little/no exercise) | BMR × 1.2 |
| Lightly active (light exercise 1–3 days/week) | BMR × 1.375 |
| Moderately active (3–5 days/week) | BMR × 1.55 |
| Very active (6–7 days/week) | BMR × 1.725 |
| Super active (hard training, physical job) | BMR × 1.9 |
This helps you determine how many calories to eat daily for:
Maintenance
Weight loss
Muscle gain
Dieters – Establish a calorie deficit or surplus
Fitness Trainers – Design client nutrition plans
Health Enthusiasts – Learn how metabolism affects energy needs
Athletes – Fine-tune calorie intake
Medical Patients – Monitor metabolic health with professional guidance
Understanding your BMR is key to effective weight management, diet planning, and overall health. The CalcNest BMR Calculator gives you a fast, reliable estimate of how many calories your body needs at rest—so you can make informed, science-backed decisions about your nutrition and fitness goals.
Use the BMR Calculator now and start managing your metabolism smarter.
Yes, it uses industry-standard equations trusted by health professionals worldwide.
BMR is your base metabolic rate at rest; TDEE adds physical activity to estimate total daily calorie needs.
Absolutely. Start with your BMR, apply your activity level, then create a calorie deficit for fat loss.
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