🧬 Basal Metabolic Rate (BMR) Calculator
Calculate resting daily calorie burn using the Mifflin-St Jeor equation.
Try the calculator
The values below are a working example. Change any field to recalculate instantly in your browser.
BMR is an estimate and can vary with body composition and health.
Formula & Mathematical Logic
BMR = 10 × Weight(kg) + 6.25 × Height(cm) - 5 × Age(y) + s
Computes exact mathematical outputs locally on your device with 0 network latency.
Step-by-Step Worked Example
Sample Scenario
A 30-year-old male weighing 70 kg at 175 cm has a BMR of ~1,650 calories per day.
Frequently Asked Questions (FAQ)
How does the Basal Metabolic Rate (BMR) Calculator work?
The Basal Metabolic Rate (BMR) Calculator applies the mathematical formula BMR = 10 × Weight(kg) + 6.25 × Height(cm) - 5 × Age(y) + s to compute your inputs 100% locally in your web browser.
Is my personal or financial data private?
Yes. Calcixa operates on a 100% privacy-first zero-backend architecture. No data leaves your device.
CALCIXA PRACTICAL GUIDE
How to use the Basal Metabolic Rate (BMR) Calculator
Basal metabolic rate (BMR) estimates the energy a body would use at rest for essential functions such as breathing, circulation, and temperature regulation. This calculator uses the Mifflin–St Jeor equation from age, sex, height, and weight.
BMR is not the same as total daily calorie need because ordinary movement, work, exercise, and digestion add expenditure. Even validated predictive equations have individual error, especially outside the population in which they were studied.
Step-by-step
- Enter measured rather than guessed height and weight.
- Provide current age and the equation’s required sex input.
- Calculate the resting-energy estimate.
- Use the calorie calculator if you also need an activity-adjusted TDEE scenario.
How to read the result
- The output is estimated kilocalories used over 24 hours at rest.
- It is an equation-based prediction, not a laboratory metabolic measurement.
- TDEE will normally be higher after activity and digestion are considered.
Common mistakes to avoid
- Calling BMR a daily eating target without considering activity.
- Using the result for children, pregnancy, or a medical condition without guidance.
- Interpreting small differences between equations as meaningful precision.
Important: This educational estimate is not medical advice or a diagnosis.
More questions about Basal Metabolic Rate (BMR) Calculator
What is the difference between BMR and TDEE?
BMR covers resting needs; TDEE estimates BMR plus activity and digestion.
Can BMR be measured directly?
Specialized indirect calorimetry can estimate resting expenditure more directly than a prediction equation.
Why does BMR change?
Body size, body composition, age, health, and measurement changes can affect it.
Sources and methodology
Calcixa explains the model, assumptions, and limitations so you can verify the result. See our calculation and tool methodology for rounding, privacy, testing, and correction practices.
Maintained by the Calcixa product team. This page was last updated on 7 September 2026.