Health & Fitness Calculators
BMR Calculator
Calculate your Basal Metabolic Rate.
US units are selected by default. Switch to metric if needed.
Calculation assumptions
- *BMR is estimated with the Mifflin-St Jeor equation.
- *BMR estimates calories burned at rest and does not include exercise or daily activity.
- *Results are estimates, not medical advice, diagnosis, or treatment guidance.
- *Needs can vary by body composition, age, health status, and activity.
Enter your values and press Calculate.
Results and breakdowns will appear here after a valid calculation.
What is BMR?
Basal Metabolic Rate (BMR) estimates the calories your body uses at rest for basic functions such as breathing, circulation, and cell activity.
This calculator uses the Mifflin-St Jeor equation: men use 10 x weight kg + 6.25 x height cm - 5 x age + 5, while women use 10 x weight kg + 6.25 x height cm - 5 x age - 161.
Worked example
Example: a 25-year-old male at 180 lb and 5 ft 10 in has an estimated BMR around 1,808 calories per day. Daily calorie needs are higher after activity is included.
Safety notes and common mistakes
BMR is not the same as daily calorie needs. It is a resting estimate and should not be used as medical advice or a treatment plan.
- Do not use BMR as your total daily calorie target without activity context.
- Do not expect one formula to match every metabolism exactly.
- Do not use the result to diagnose or manage a medical condition.
- Pregnant people, people under 18, older adults, athletes, and anyone with a medical condition should use professional guidance.
Transparency note
Accuracy and limitations
Calzivo tools are built for practical estimates, conversions, and checks. Some tools use standard formulas or simplified assumptions, and results can be affected by input accuracy, rounding, units, local rules, or changing official requirements.
Health and fitness results are estimates, not medical advice. Formulas simplify real bodies and cycles, so important health decisions should be checked with a qualified clinician.
How to Use This Tool
Use these steps to enter the right inputs and interpret the result correctly.
Choose US or Metric units.
Enter your gender, age, weight, and height.
The calculator will determine your BMR instantly.
Use this number as a baseline for your nutrition planning.
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Related Guides
Background reading and explanations related to BMR Calculator.
Frequently Asked Questions
Common questions about BMR Calculator and how to read the result.
How is BMR different from TDEE?
BMR is what you burn at rest. TDEE includes BMR plus the calories burned through physical activity.
Which formula does this BMR calculator use?
It uses the Mifflin-St Jeor equation with weight, height, age, and gender.
Is BMR a calorie goal?
Not by itself. BMR is a resting estimate. Most people need more calories than BMR once daily activity is included.
Can BMR change?
Yes. Weight, age, body composition, health status, and activity changes can affect energy needs.
Is this medical advice?
No. Results are estimates and should not be used to diagnose, treat, or manage a medical condition.
Who should use professional guidance?
People who are pregnant, under 18, older adults, athletes, or anyone with a medical condition should use professional guidance.