BMI & Body Health
Instant health index and target weight range breakdown.
BMI & Body Health
Compute Body Mass Index with Metric or Imperial standard units.
- Underweight< 18.5
- Normal weight18.5 – 24.9
- Overweight25 – 29.9
- Obese30+
Standard recommended weight bracket for your height profile.
View category ranges as a table
| Category | BMI range (kg/m²) |
|---|---|
| Underweight | < 18.5 |
| Normal weight | 18.5 – 24.9 |
| Overweight | 25 – 29.9 |
| Obese | 30+ |
Formula & assumptions
- BMI formula Formula
- BMI = weight (kg) / height (m)². Imperial inputs are converted exactly (1 lb = 0.45359237 kg, 1 in = 0.0254 m) before the same formula runs.
- Category cut-offs Published data
- WHO adult cut-offs for people 18 and over: underweight below 18.5, normal 18.5–24.9, overweight 25–29.9, obese 30 and above. The dial, legend and table above all read these from the same list. WHO classification of BMI
- Healthy weight range Formula
- The span of weights that lands inside the normal band for your height: 18.5 × height² to 24.9 × height².
- Your measurements Your input
- Weight and height are user-entered; a wrong or stale measurement shifts everything this tool reports.
BMI is one screening number. It does not measure body fat, fitness or health risk, and it is not diagnostic — individual decisions need a healthcare professional.
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What This Calculator Does
The BMI Calculator computes your Body Mass Index from weight and height and classifies it against the WHO standard ranges. It also reveals the healthy weight band for your height so you can see where you fall.
How It Works
BMI is weight in kilograms divided by height in meters squared. The result maps onto standard categories: underweight below 18.5, normal 18.5-24.9, overweight 25-29.9, and obese 30 and above. Healthy weight is the range producing a BMI in the normal band.
Example
At 70 kg and 175 cm, BMI is 70 / (1.75 x 1.75) = 22.9, comfortably in the normal range. The healthy band for that height spans roughly 56.6 to 76.3 kg.
Formula
BMI = Weight (kg) / Height (m)²Weight = BMI × Height (m)²For BMI 18.5–24.9.
Reading the Results
Body Mass Index
Your weight scaled to height, classified by the WHO standard ranges shown in the category badge.
Healthy Weight Range
The weight band for your height that produces a BMI in the normal 18.5–24.9 range.
Frequently Asked Questions
Is BMI accurate for everyone?
BMI is a useful population-level screen but can misclassify muscular athletes, who may appear overweight despite low body fat.
What is a healthy BMI range?
The WHO defines 18.5 to 24.9 as normal weight, with under 18.5 underweight and 25+ overweight or obese.
Does BMI account for body composition?
No. For a fuller picture, pair BMI with waist circumference or body-fat percentage, such as the body-fat calculator on this site.