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BMI Calculator

BMI Calculator

Adult BMI with optional waist-to-height context.

InputsAdult modeMetric unitsLive

Optional central-adiposity check (NICE: waist should stay under half of height).

Adult BMI

22.86

BMI Prime 0.914

Category

Healthy Weight

Bands: <18.5 underweight · 18.5-24.9 healthy · 25-29.9 overweight · 30+ obesity

Healthy range

56.7-76.3 kg

Target BMI 22

67.4 kg

Clinical notesscope and limits

Screening estimate only. Combine BMI with clinical context such as body composition, blood pressure, lab findings, and medical history.

Child and teen interpretation is percentile-based. This tool links to CDC guidance for ages 2-19 instead of showing adult category bands.

CDC percentile reference: Child and teen BMI calculator

Formula
BMI = weight(kg) / height(m)^2; waist-to-height ratio = waist / height
\text{WHtR} = \frac{w}{h}
  • Convert metric or imperial measurements to kilograms and meters.
  • Square height in meters.
  • Divide weight in kilograms by squared height.
  • If waist is supplied, divide waist circumference by height using the same units.
Example

Worked example: 70 kg and 175 cm

  1. 1 Height = 1.75 m
  2. 2 BMI = 70 / (1.75^2)
  3. 3 BMI = 22.86

BMI is about 22.86.

How
  1. Confirm that the person is age 20 or older, then choose metric or imperial units.
  2. Enter weight and height; optionally enter waist circumference for added central-adiposity context.
  3. Review the adult BMI category, reference weight range, and screening limitations.
Avoid
  • Using centimeters directly in formula without converting to meters.
  • Treating BMI category as diagnosis.
  • Applying adult categories to children or teens.
  • Treating the reference weight range as an individualized weight prescription.

Ref only. Not medical advice.

FAQ
Is BMI a medical diagnosis?

No, BMI is a screening metric and not a standalone medical diagnosis.

Can children use this same interpretation?

No. Ages 2 through 19 require age- and sex-specific BMI-for-age percentiles.

What unit should I enter?

Choose metric for kilograms and centimeters, or imperial for pounds, feet, and inches.

What does waist-to-height ratio add?

It provides optional central-adiposity context. NICE advises keeping waist circumference below half of height.

Does BMI measure body fat?

No. BMI does not directly account for muscle mass, bone density, or body composition and should be considered with other health factors.

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