Free Health Tool

BMI Calculator
for Adults

Get your Body Mass Index score instantly. Works in metric & imperial units. Trusted by millions.

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cm
kg
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Your BMI
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Underweight Normal Overweight Obese

📊 BMI Categories (WHO)

Underweight Below 18.5
Normal weight 18.5 – 24.9
Overweight 25.0 – 29.9
Obese Class I 30.0 – 34.9
Obese Class II 35.0 – 39.9
Obese Class III 40.0 +

💡 Quick Health Tips

🥦Eat whole foods and vegetables daily to maintain a healthy BMI range.
🚶30 minutes of moderate walking per day can significantly reduce BMI.
💧Staying hydrated helps your metabolism and reduces unnecessary calorie intake.
😴Poor sleep is linked to weight gain. Aim for 7–9 hours per night.

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Pregnancy Due Date
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Water Intake Calculator

What is BMI?

Body Mass Index (BMI) is a simple calculation using your height and weight to estimate whether you are at a healthy weight. It is widely used by doctors and health professionals as a quick screening tool.

BMI is calculated by dividing your weight in kilograms by your height in meters squared (kg/m²). While it does not directly measure body fat, it correlates well with direct measures of body fat for most people.

The World Health Organization (WHO) uses BMI to define healthy weight ranges for adults aged 18 and over, regardless of age or gender.

How to Use This Calculator

Step 1: Choose your preferred unit system — Metric (kg/cm) or Imperial (lb/ft).

Step 2: Select your biological sex and enter your age. BMI interpretation can vary slightly by age.

Step 3: Enter your height and weight accurately, then click "Calculate My BMI."

Step 4: Review your BMI score and category. Use the health tips to understand what it means for your wellbeing.

Frequently Asked Questions

Is BMI accurate for everyone? ▼
BMI is a useful screening tool but has limitations. It may overestimate body fat in athletes with high muscle mass and underestimate it in older adults who have lost muscle. It also does not distinguish between fat, muscle, and bone mass.
What is a healthy BMI for adults? ▼
According to the World Health Organization, a BMI between 18.5 and 24.9 is considered a healthy or normal weight range for adults. However, ideal BMI can vary by ethnicity and individual health conditions.
How do I lower my BMI? ▼
A combination of a balanced, calorie-controlled diet and regular physical activity is the most effective way to lower BMI. Aim for at least 150 minutes of moderate exercise per week. Consult a doctor or dietitian for a personalized plan.
Does BMI apply to children? ▼
BMI is calculated differently for children and teens (ages 2–19) using age- and gender-specific percentile charts. This calculator is designed for adults 18 and older.
What is the BMI formula? ▼
Metric: BMI = weight (kg) ÷ height² (m). Imperial: BMI = 703 × weight (lb) ÷ height² (inches). For example, a person weighing 70 kg at 170 cm has a BMI of 70 ÷ (1.70 × 1.70) = 24.2.
⚕️ Medical Disclaimer: This BMI calculator is provided for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. BMI is a screening tool and not a diagnostic measure. Always consult a qualified healthcare provider before making any decisions about your health or lifestyle based on this calculator's results.