BMR Calculator: A Practical Guide
Use the BMR Calculator to estimate resting energy needs from age, weight, height and the sex coefficient used by the equation. The result is expressed in kilocalories per day. It is a mathematical estimate, not a measured metabolism test or a daily eating prescription.
How to Use BMR Calculator
- Choose the sex coefficient available in the form.
- Enter age in years, weight in kilograms and height in centimetres.
- Select Calculate BMR.
- Treat the result as a resting estimate before considering activity and personal health needs.
Mifflin–St Jeor Resting-Energy Estimate
The implemented equation is 10 × weight + 6.25 × height − 5 × age, plus 5 for the male coefficient or minus 161 for the female coefficient. Weight is in kg and height is in cm.
The formula predicts resting energy expenditure. Movement, exercise and digestion contribute to daily expenditure beyond this estimate. It does not adapt to illness, pregnancy, individual body composition or a measured metabolic rate.
Worked Example
For a 30-year-old male coefficient, 70 kg and 175 cm: 700 + 1093.75 − 150 + 5 = 1648.75 kcal/day.
This is not a recommendation to eat exactly 1649 kcal. A daily maintenance estimate also needs an activity assumption, and personal dietary advice requires more context.
Include an activity multiplier: use the Calorie Calculator.
Calculate a separate height-to-weight screening measure: use the BMI Calculator.
Checks and Common Mistakes
- Do not enter height in metres in a centimetre field.
- Do not mistake resting energy for total daily expenditure.
- Avoid using this adult estimation workflow for children or pregnancy.
- The form has two equation coefficients; it does not model all individual physiological circumstances.
Frequently Asked Questions
Is this a laboratory measurement?
No. A measured resting metabolic rate requires an appropriate clinical method. The calculator uses an equation and the measurements you provide.
Should I eat less than my BMR to lose weight?
This output does not establish a safe intake target. Discuss an appropriate plan with a clinician or dietitian rather than using the resting estimate as a restriction rule.
Why is my calorie-calculator result higher?
A maintenance-calorie model multiplies the resting estimate by an activity factor. Those outputs answer different questions.
Related Tools for the Next Step
- Calorie Calculator: Include an activity multiplier.
- BMI Calculator: Calculate a separate height-to-weight screening measure.
- Weight Converter: Prepare weight in kilograms.
- Length Converter: Prepare height in centimetres.
Reference
Further reading: Original Mifflin–St Jeor study.