By Zencalcy Editorial TeamLast reviewed About us
This tool classifies weight status from height and weight using adult BMI ranges. It also shows the weight range linked to a BMI of 18.5–24.9 and a ponderal index for context. BMI is a screening measure, not a diagnosis, and it does not distinguish muscle from fat.
Check BMI, weight status and healthy weight range.
BMI = weight(kg) ÷ height(m)² Ponderal index = weight(kg) ÷ height(m)³ Healthy range = 18.5–24.9 × height(m)²
Adult BMI categories are under 18.5 underweight, 18.5–24.9 healthy, 25.0–29.9 overweight, and 30 or above obesity. BMI thresholds differ for children, pregnancy and some ethnic groups.
| Symbol | Meaning |
|---|---|
| BMI | Body mass index in kg/m². |
| Ponderal index | Weight divided by height cubed. |
| Healthy range | Weights corresponding to BMI 18.5–24.9 at your height. |
BMI = 80 ÷ 1.75² = 26.1, which is in the overweight range. The healthy range at 1.75 m is 56.7–76.3 kg, so 80 kg is about 3.7 kg above the upper bound. Ponderal index is 80 ÷ 1.75³ = 14.9.
BMI is cheap, quick and good at describing populations. It is weaker at describing individuals. A rugby player and a sedentary office worker can share a BMI of 27 with completely different body composition and risk. Waist circumference adds the missing distribution information: a large waist suggests visceral fat, which is more strongly linked to metabolic disease than fat on the hips. Ethnicity also matters, with several guidelines using lower BMI thresholds for people of South Asian descent. Age changes the picture too, because muscle mass falls and body fat rises without necessarily changing weight. The sensible use of this calculator is as a starting point: if BMI is outside the healthy band, check waist, blood pressure and glucose rather than assuming the number tells the whole story.
Continue with the ABSI Calculator (A Body Shape Index), Adjusted Body Weight Calculator, or the BAI Calculator (Body Adiposity Index) — or browse more body measurements tools and all health calculators.
Also see the Body Fat Calculator.
Not automatically. BMI is a population screening tool. Fitness, waist circumference, blood pressure, glucose and family history matter. Some people with a BMI in the overweight range are metabolically healthy; others with a 'normal' BMI carry risk.
Every result is a screening estimate from published anthropometric equations, not a diagnosis or a measurement of body composition. Tape measurements should be taken snugly against the skin without compressing it, at the landmarks named in each tool. Equations were derived in specific populations and can be less accurate for athletes, older adults, children, pregnant people and people with significant oedema.
Reference material used to build and check this calculator:
Last reviewed: September 2026. See how we build and check every tool on the about page.
Content updated: September 2026