How it works
Calculate adult BMI from metric or imperial measurements and see the WHO adult weight-status band.
Enter your weight and height in metric or imperial units; the calculator converts to the shared formula BMI = kg ÷ m². The category uses the WHO adult cut-offs (under 18.5, normal 18.5–24.9, overweight 25–29.9, obese 30 and above) and the screening range shows the weight interval corresponding to BMI 18.5–24.9 for your height. BMI is a screening metric for populations and individuals — it is not a diagnosis and does not measure body fat, muscle or metabolic health.
Formula
BMI = weight (kg) ÷ height (m)². Imperial: kg = lb × 0.45359237 and m = in × 0.0254. Adult bands: <18.5 underweight · 18.5–24.9 normal weight · 25–29.9 overweight · ≥30 obese.
weight- Body weight (kg or lb)
height- Height (cm or in)
BMI- Body mass index (kg/m²)
Examples
- 70 kg, 175 cmMetric · weight 70 kg · height 175 cmBMI 22.9 — normal weight (WHO adult band)
- 154.3 lb, 68.9 inImperial · weight 154.3 lb · height 68.9 inBMI 22.9 — normal weight (WHO adult band)
Frequently asked questions
Is BMI a diagnosis?
No. BMI is a screening metric. It does not diagnose body fat percentage, metabolic health, disease or fitness, and it cannot replace a clinical assessment.
Does this apply to children and teenagers?
No. The adult cut-offs here are not valid for children or adolescents, who need age- and sex-specific percentile charts. Use a paediatric growth reference for them.
When is BMI less informative?
It can be less informative during pregnancy, for very muscular people and for older adults, because it does not distinguish muscle from fat or account for body composition changes.
What is the screening range?
It is the weight interval for your height that corresponds to the WHO normal band (BMI 18.5–24.9), shown in the unit you selected. It is a reference interval, not a personal target.
How to read the result
The BMI number and its band are a quick population-level screening. Read it together with the limitations above and, for personal health decisions, with a qualified professional.
Limitations
Adult classification only. Not medical advice, not a diagnosis and not a treatment recommendation. Pregnancy, high muscularity and older age reduce its informativeness.
Source: WHO adult BMI classification — World Health Organization, "Obesity and overweight" fact sheet (who.int/news-room/fact-sheets/detail/obesity-and-overweight). Adult cut-offs: 18.5 / 25 / 30.