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Free BMI calculator for adults: enter height and weight in kg/cm or lb/ft-in to get BMI (kg/m²), WHO weight category, BMI Prime, Ponderal Index, and the 18.5–25 healthy weight band for your height.
Last updated: May 24, 2026
Ages 2–19? BMI percentile calculator
BMI
20.1 kg/m²
Normal
BMI Prime
0.8
Ponderal Index
11.1 kg/m³
Healthy weight (BMI 18.5–25)
59.9 – 81 kg
Screening only — not medical diagnosis. Athletes may need body-fat or waist measures too.
20.1 kg/m²
65 kg · 180 cm · Normal
59.9–81 kg
BMI 18.5–25 at 180 cm
0.8
Ponderal Index: 11.1 kg/m³
Metric · 180 cm, 65 kg
20.1
Normal
US · 5′10″, 160 lb
23
Normal
180 cm, 97 kg
29.9
Overweight
180 cm, 100 kg
30.9
Obese Class I
Metric: BMI = kg ÷ m² — e.g. 65 ÷ 1.80² = 20.1
US: BMI = 703 × lb ÷ in² — e.g. 703 × 160 ÷ 70² = 23
BMI Prime: BMI ÷ 25 = 0.8 (default example)
Ponderal Index: kg ÷ m³ = 11.1
| Classification | BMI (kg/m²) |
|---|---|
| Severe Thinness | < 16 |
| Moderate Thinness | 16 – 16.9 |
| Mild Thinness | 17 – 18.4 |
| Normal | 18.5 – 24.9 |
| Overweight | 25 – 29.9 |
| Obese Class I | 30 – 34.9 |
| Obese Class II | 35 – 39.9 |
| Obese Class III | ≥ 40 |
| Category | Percentile |
|---|---|
| Underweight | < 5th |
| Healthy weight | 5th – 85th |
| At risk of overweight | 85th – 95th |
| Overweight | > 95th |
Use the pediatric BMI percentile calculator — adult cutoffs do not apply to growing children.
| BMI Prime | Meaning |
|---|---|
| < 0.74 | Underweight vs normal upper limit (25) |
| 0.74 – 1.0 | Within normal BMI band |
| 1.0 – 1.2 | Overweight |
| > 1.2 | Obese threshold (BMI > 30) |
23 kg/m²
Normal
Healthy band: 128.9–174.2 lb
15.4 kg/m²
Severe Thinness
9.9 kg/m²
Use pediatric percentiles — not adult WHO labels.
Share with anyone tracking weight goals
Suggested hashtags: #BMI #Health #Fitness #BodyMassIndex #Calculator