BMI Calculator

• A single reading is a snapshot; trends across weeks are more clinically meaningful.
• Body-composition metrics matter more than weight alone for most goals.
• Baseline varies by age and sex — compare to your own history, not population averages.

1. 1Enter each input value into the calculator above.
2. 2Review the result and any auto-generated breakdowns.
3. 3Adjust inputs to compare scenarios.
4. 4Copy, share, or print the results.

• Anyone tracking a personal health metric
• Coaches setting goals with clients
• Clinicians running quick screens
• Researchers estimating population averages

• When setting a personal health goal
• At routine checkups
• When tracking progress over weeks or months

• Units used (kg vs lb, cm vs in)
• Age, sex and activity level
• Underlying medical conditions

Illustrative examples using U.S. market averages. Enter your own numbers above for a personalized figure.

• Entering values in the wrong units.
• Assuming the result includes taxes or fees when it may not.
• Using rounded inputs and expecting exact figures.

• Use consistent units and measurement times for comparable results.
• Any single reading is a snapshot — trend over weeks matters more.
• Discuss significant changes with a qualified clinician.

• Uses formulas published by CDC, WHO and NIH.
• Metric and imperial units supported everywhere.
• No account, no tracking, no data sold — your inputs stay in your browser.
• Companion educational content explains what each number means.

• Educational only — not a diagnosis and not a substitute for medical advice.
• Population averages don't capture individual variation.
• Talk to a qualified clinician before making changes to your care.

BMI (Body Mass Index)

Weight in kg divided by height in metres squared. A screening indicator only — it doesn't distinguish muscle from fat.

BMR (Basal Metabolic Rate)

The calories your body burns at complete rest to maintain vital functions.

TDEE

Total Daily Energy Expenditure — BMR multiplied by an activity factor. Your maintenance calorie level.

Macronutrients

Protein, carbohydrates, and fat — the three energy-providing components of food.

• Take measurements at the same time of day under similar conditions.
• Use trends across 2–4 weeks, not any single reading, to judge progress.
• Discuss significant changes with a licensed clinician before adjusting habits.
• Keep units consistent (metric or imperial) across every entry.

The formulas, rates and definitions used by this calculator are aligned with the following official sources:

• World Health Organization — BMI classification — Adult BMI categories used by health authorities worldwide.
• U.S. National Institutes of Health (NIH) — Reference BMI / calorie / BMR formulas.
• Centers for Disease Control and Prevention (CDC) — Adult and child health reference ranges.

We use only primary sources — regulators, standards bodies and scheme operators. See our full sourcing policy for details. Sources & References Policy · Calculator Methodology · How We Verify Formulas

We continuously review and improve our calculators to keep formulas, assumptions and references accurate.

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