What is BMI and how is it calculated?

BMI (Body Mass Index) estimates body fat using height and weight. Formula: metric: BMI = kg / (m^2); imperial: BMI = 703 × (lb / in^2).

What are the BMI categories?

Underweight: <18.5, Healthy weight: 18.5–24.9, Overweight: 25–29.9, Obesity: ≥30 (adult guidance).

Is this BMI calculator accurate?

It uses the standard BMI formulas. BMI is a screening tool and does not directly measure body fat. Athletes, pregnant people, and different body types may need additional measures (e.g., waist circumference).

Yes. All calculations run locally in your browser. We do not upload or store your inputs.

Does it support metric and imperial units?

Yes. Enter kg/cm or lb/ft/in. The calculator converts and shows your healthy weight range based on your height.

Is BMI the same for children and teens?

No. For people under 20, BMI is age- and sex-specific (BMI-for-age percentiles). Consult pediatric charts or a clinician.

BMI Calculator: Check Your Body Mass Index

Q: What are the BMI categories?

Underweight: <18.5, Healthy weight: 18.5–24.9, Overweight: 25–29.9, Obesity: ≥30 (adult guidance).

Q: Is this BMI calculator accurate?

It uses the standard BMI formulas. BMI is a screening tool and does not directly measure body fat. Athletes, pregnant people, and different body types may need additional measures (e.g., waist circumference).

Q: Is my data private?

Yes. All calculations run locally in your browser. We do not upload or store your inputs.

Q: Does it support metric and imperial units?

Yes. Enter kg/cm or lb/ft/in. The calculator converts and shows your healthy weight range based on your height.

Q: Is BMI the same for children and teens?

No. For people under 20, BMI is age- and sex-specific (BMI-for-age percentiles). Consult pediatric charts or a clinician.

Get a clear, simple, and accurate snapshot of your health. Use our free online tool to instantly calculate your BMI and discover your ideal weight range.

Height (cm)

Weight (kg)

Fast, Free, Private BMI Calculator

Instantly check your Body Mass Index (BMI) with metric or imperial units and see your healthy weight range. Top, fast, best and lifetime free unlimited your information is 100% confidential and secure (processing is done locally in your browser).

Why people love this BMI calculator

Metric & Imperial

Use kg/cm or lb/ft/in. Automatic conversions and healthy weight range by height.

Clear categories

Instant results with Underweight, Healthy, Overweight, or Obese labels and a visual gauge.

Private by design

No uploads, no tracking. Everything runs locally on your device.

Accurate formula

Uses the standard BMI formula (kg/m² or 703×lb/in²) used by health professionals.

Free & unlimited

Lifetime free no signups, no paywalls, no watermarks, no limits.

Mobile friendly

Optimized for Chrome, Edge, Firefox, and Safari on desktop and mobile.

What is BMI?

BMI (Body Mass Index) is a screening measure that estimates body fat based on height and weight. It helps identify potential health risks related to weight.

BMI formula

Metric: BMI = weight (kg) / [height (m)]²
Imperial: BMI = 703 × weight (lb) / [height (in)]²

Adult BMI categories

Underweight: < 18.5
Healthy weight: 18.5–24.9
Overweight: 25–29.9
Obesity: ≥ 30

Note: BMI is a general guide for adults 20+. It may not reflect body fat for athletes, pregnant people, or all body types. Consider other measures like waist circumference.

How to calculate your BMI

Select Metric (kg/cm) or Imperial (lb/ft/in).
Enter your height and weight.
Click “Calculate BMI” to see your BMI, category, and healthy weight range.

Popular uses worldwide

Fitness & Wellness

Track progress in gyms, home workouts, and wellness programs.

Telehealth & Clinics

Quick screening for online consultations and health checkups.

Schools & Universities

Basic health education for adults and community programs.

Research & Surveys

Standardized metric for population health studies.

Insurance & HR

General screening when allowed by policy and local regulations.

Personal Health

Get a quick snapshot of weight-related health risk.

Always consult a qualified professional for personalized advice.

Global availability (GEO)

Built for users in the USA, UK, Canada, Australia, India, EU (Germany, France, Spain, Italy, Netherlands), Middle East (UAE, Saudi Arabia), Asia (Singapore, Malaysia, Philippines, Indonesia, Japan, South Korea), Africa (Nigeria, South Africa, Egypt), and Latin America (Brazil, Mexico, Argentina). Metric & imperial units included if your browser works, our BMI calculator works.

Frequently Asked Questions

Is it private and secure?

Yes. All calculations happen in your browser. Your data never leaves your device.

Which units can I use?

Both metric (kg/cm) and imperial (lb/ft/in). We also show your healthy weight range by height.

What is a good BMI?

For most adults, healthy weight is BMI 18.5–24.9. Talk to a clinician for personal guidance.

Are results medical advice?

No. BMI is a screening tool. For diagnosis and treatment, speak with a healthcare professional.

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