Body Mass Index (BMI) & Healthy Weight Range Calculator
Calculate your BMI and discover your healthy weight range. BMI is a widely used screening tool to categorize weight status relative to height.
Formula
Metric:
BMI = weight(kg) ÷ height(m)²
Imperial:
BMI = 703 × weight(lb) ÷ height(in)²
Healthy Weight Range (from height):
Min weight = 18.5 × height(m)²
Max weight = 24.9 × height(m)²
BMI Categories (WHO standard):
- Below 18.5 — Underweight
- 18.5 – 24.9 — Normal weight
- 25.0 – 29.9 — Overweight
- 30.0 – 34.9 — Obesity Class I
- 35.0 – 39.9 — Obesity Class II
- 40.0 and above — Obesity Class III (Severe)
Assumptions & References
- BMI is a population-level screening tool and does not directly measure body fat percentage.
- BMI may overestimate body fat in muscular individuals and underestimate it in older adults with low muscle mass.
- Standard WHO BMI categories are used; some health organisations use adjusted thresholds for certain ethnic groups (e.g., Asian populations: overweight ≥ 23, obese ≥ 27.5).
- BMI categories for children and teens (ages 2–19) use age- and sex-specific percentiles; the adult formula is shown here.
- Imperial conversion factor 703 = 1 kg/m² expressed in lb/in² units.
- References: World Health Organization (WHO) BMI classification; CDC BMI guidelines; NIH Clinical Guidelines on Obesity.
- This calculator is for informational purposes only and does not constitute medical advice. Consult a healthcare professional for personalised guidance.