BMI Calculator
Calculate your patient’s Body Mass Index (BMI) instantly with this free, nurse-focused calculator. Assess weight status using clinical standards—ideal for bedside care, nursing students, and exam prep.
BMI Calculator
Healthy BMI range: 18.5 – 24.9
Note: BMI is a general guide and does not diagnose body fatness or health. For personalized advice, consult a healthcare provider.
References: WHO, CDC
BMI Calculator: Understand Your Body Mass Index
Learn what your Body Mass Index (BMI) means, how it is calculated, health risks, and its limitations. Use our free BMI Calculator above to check your result instantly.
🧮 What Is BMI?
Body Mass Index (BMI) is a simple screening formula:
BMI = weight (kg) ÷ height² (m²)
It gives a quick indication of whether you are underweight, normal weight, overweight, or obese.
Example: Height = 1.70 m, Weight = 65 kg → BMI = 22.5 (Normal range).
📊 BMI Categories (WHO & CDC)
- Underweight: BMI < 18.5
- Normal weight: 18.5 – 24.9
- Overweight: 25.0 – 29.9
- Obesity (Class I): 30.0 – 34.9
- Obesity (Class II): 35.0 – 39.9
- Severe Obesity (Class III): ≥ 40.0
✅ Why Use a BMI Calculator?
- Quick screening tool for weight-related risks.
- Standardized measure across populations.
- Track changes over time during lifestyle adjustments.
⚠️ Limitations of BMI
BMI is not perfect — it does not measure muscle mass, bone density, or fat distribution. Athletes, children, and elderly may need additional assessments.
That’s why healthcare providers often add waist circumference, body fat %, and lab results to get a complete picture.
🩺 Health Risks by BMI
- Underweight: Malnutrition, osteoporosis, anemia.
- Overweight: High blood pressure, diabetes, heart disease.
- Obesity: Cardiovascular disease, sleep apnea, cancers.
🔍 Beyond BMI: Other Tools
At Nurses Professional Education we also provide:
- MAP Calculator — mean arterial pressure for blood pressure health.
- Anion Gap Calculator — checks metabolic balance.
- Burn Calculator — for accurate burn %TBSA estimation.
📅 BMI for Children vs Adults
For adults, BMI thresholds are fixed. For children and teens, BMI is interpreted using percentile charts by age and sex.
🔗 Reference: CDC Child BMI Percentiles
🤔 Frequently Asked Questions
How accurate is BMI?
It is a good screening tool but not a diagnostic test. It should be combined with clinical evaluation.
Is a high BMI always unhealthy?
Not always. Athletes with high muscle mass may have a high BMI but low body fat.
What’s a healthy BMI?
For most adults, 18.5 – 24.9 is considered healthy.
Should I lose weight if my BMI is over 25?
Not automatically. Talk with your doctor. Lifestyle changes may be recommended depending on your overall health.