BMI & Ideal Body Weight Calculator
Enter height and weight to calculate BMI and Ideal Body Weight. IBW uses the Devine formula, which is widely used for drug dosing (e.g., GLP-1 agonists, insulin, antibiotics).
Units
—
BMI (kg/m²)
—
Ideal Body Weight
BMI Formula: weight(kg) ÷ height(m)²
Ideal Body Weight (Devine formula):
Male: 50 kg + 2.3 kg per inch over 5 feet
Female: 45.5 kg + 2.3 kg per inch over 5 feet
Adjusted Body Weight (if BMI > 30): IBW + 0.4 × (Actual Weight − IBW) — used for some medication dosing.
Want your ideal weight by four formulas plus a healthy weight range? Use the Ideal Body Weight Calculator.
Ideal Body Weight (Devine formula):
Male: 50 kg + 2.3 kg per inch over 5 feet
Female: 45.5 kg + 2.3 kg per inch over 5 feet
Adjusted Body Weight (if BMI > 30): IBW + 0.4 × (Actual Weight − IBW) — used for some medication dosing.
Want your ideal weight by four formulas plus a healthy weight range? Use the Ideal Body Weight Calculator.
BMI Classification (WHO/NIH)
| BMI (kg/m²) | Classification | Clinical Notes |
|---|---|---|
| < 18.5 | Underweight | Evaluate for malnutrition, eating disorders, hyperthyroidism, adrenal insufficiency |
| 18.5 – 24.9 | Normal weight | Maintain healthy habits; assess for central adiposity if metabolic concerns |
| 25.0 – 29.9 | Overweight | Lifestyle intervention; screen for metabolic syndrome, prediabetes, NAFLD |
| 30.0 – 34.9 | Obesity Class I | Weight loss therapy; GLP-1 agonists, metformin discussion appropriate |
| 35.0 – 39.9 | Obesity Class II | Intensive management; bariatric surgery consultation may be appropriate |
| ≥ 40.0 | Obesity Class III (Severe) | High surgical candidacy; significant comorbidity reduction with weight loss |
Asian populations: ADA and WHO recommend lower thresholds for overweight (≥23 kg/m²) and obesity (≥25 kg/m²) in Asian individuals due to higher cardiometabolic risk at lower BMIs.
In the Houston area?
Have questions about weight or metabolism? See an endocrinologist.
Medical weight management, GLP-1 therapy and metabolic care, at Endocrine & Diabetes Plus in Sugar Land and Memorial City. New patients are usually seen within 2 weeks; the earliest openings are with Dr. Chhavi Chadha. Telehealth follow-ups for patients anywhere in Texas.
Outside Texas? Share this result with your own doctor. This tool is for information only.
⚕️ Clinical note: BMI does not measure body fat directly and may misclassify individuals with high muscle mass, older adults, or those with sarcopenic obesity. Waist circumference and body composition testing provide additional context. IBW (Devine formula) is an estimate used for dosing calculations — not a weight goal. Weight targets for treatment should be individualized with your provider.