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BMI Calculator

Calculate your Body Mass Index (BMI) using metric or imperial units. Get your BMI category and an estimated healthy weight range.

How to calculate Formula BMI Chart
Informational only — not medical advice.

Calculate your BMI

Result
Enter your details and press Calculate.
Adult categories commonly used: Underweight (<18.5), Healthy (18.5–24.9), Overweight (25–29.9), Obesity (≥30). For kids/teens, BMI is interpreted by percentile (age + sex), not adult cutoffs. Learn more →

Fast

Lightweight calculator that works instantly on mobile.

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No account required. Your inputs stay in your browser in this page.

Clear explanation

Shows formula, category, and when BMI can be misleading. Read the formula →

How BMI is calculated

BMI estimates weight relative to height. It’s commonly used as a screening metric—not a diagnosis.

  • BMI = weight (kg) / height (m)²
  • BMI = 703 × weight (lb) / height (in)²

BMI may be less accurate for very muscular people, pregnancy, or children/teens (percentiles needed).

Step-by-step guide Full formula page

Example

Height 175 cm (1.75 m), weight 70 kg:

BMI = 70 / (1.75 × 1.75) = 22.9

BMI ranges (adults)

Commonly used BMI categories for adults:

Open BMI Chart

Underweight

< 18.5

Healthy weight

18.5–24.9

Overweight

25.0–29.9

Obesity

30.0+

Tip: If you want a printable BMI chart later, generate it as a PDF to keep the page lightweight and fast.

Kids & teens: BMI uses percentiles

For children and teens, BMI is interpreted by percentile using age and sex—not adult BMI cutoffs. If you plan a kids tool, it must ask for age + sex and output percentile.

Kids & teens guide

Don’t do this

Publishing a “kids BMI calculator” using adult categories makes your site look unreliable.

References

Cite reputable public health sources to build trust:

Medical disclaimer: BMIHelper provides general information only. It is not medical advice. If you have health concerns, consult a qualified clinician.