Calculate Your BMR
Use this basal metabolic rate (BMR) calculator to estimate how many calories your body burns each day at complete rest.
BMR is your baseline. Activity level helps estimate maintenance calories (TDEE).
What is BMR?
Basal Metabolic Rate (BMR) is the number of calories your body needs to keep you alive at complete rest. Think breathing, circulation, hormone production, body temperature regulation, and cell repair. Even if you stayed in bed all day, your body would still burn calories to run these essential systems.
A basal metabolic rate BMR calculator gives you a practical starting point for nutrition planning. Whether your goal is fat loss, muscle gain, or weight maintenance, understanding your baseline energy needs helps you make better decisions.
How this BMR calculator works
Mifflin-St Jeor equation
This page uses the Mifflin-St Jeor formula, one of the most commonly used equations in sports nutrition and diet coaching:
- Male: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
- Female: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
If you choose imperial units, this calculator automatically converts pounds and feet/inches into kilograms and centimeters before applying the formula.
BMR vs TDEE
BMR is your resting calorie burn. Total Daily Energy Expenditure (TDEE) is BMR multiplied by an activity factor. TDEE estimates how many calories you burn in a real day that includes movement and exercise.
How to use your results
- Weight maintenance: Start near your estimated TDEE and track body weight weekly.
- Fat loss: Aim for about 300–500 calories below maintenance.
- Muscle gain: Aim for about 200–350 calories above maintenance with strength training.
- Performance: Use maintenance calories as a baseline, then adjust for training volume.
If your body weight does not change as expected after 2–3 weeks, adjust daily calories by 100–200 and reassess.
What affects basal metabolic rate?
Body size and composition
Larger bodies generally burn more calories at rest. Muscle tissue is also more metabolically active than fat tissue, so people with more lean mass often have a higher BMR.
Age and hormones
BMR tends to decline with age, partly due to changes in muscle mass and hormonal environment. Thyroid function and other endocrine factors can significantly influence resting metabolism.
Sleep, stress, and dieting history
Chronic sleep deprivation, high stress, and repeated crash dieting can alter appetite, recovery, and daily energy output. While BMR formulas provide a useful estimate, your real-world calorie needs can drift over time.
Tips for better calorie planning
- Track your body weight 3–4 times per week and use a weekly average.
- Keep protein intake consistent, especially during a fat-loss phase.
- Measure portions for 1–2 weeks to improve accuracy.
- Use progress photos, waist measurements, and training performance—not scale weight alone.
- Recalculate BMR after meaningful weight changes.
Important note
A BMR calculator is an estimate, not a diagnosis. Medical conditions, medications, and individual metabolism can affect your true energy needs. If you have a health condition or a history of disordered eating, consult a qualified healthcare professional before making aggressive dietary changes.