Why use this calculator
BMI is a widely-used screening tool to assess if your weight is in a healthy range relative to your height. While not perfect, it provides a quick baseline measurement used by healthcare providers worldwide.
How to use it
Select your preferred unit system (imperial or metric), then enter your weight and height. The calculator determines your BMI and corresponding health category according to WHO standards. The healthy weight range is displayed in your selected units.
The formula
BMI = Weight (kg) / Height (m)². Categories: Underweight < 18.5, Normal 18.5-24.9, Overweight 25-29.9, Obese ≥ 30.
Worked examples
170 lbs at 5'10" (imperial)
BMI of 24.4 — Normal weight
77 kg at 178 cm (metric)
BMI of 24.3 — Normal weight
When people use it
- Health screening
- Weight management planning
- Fitness goal setting
Tips
- BMI doesn't distinguish between muscle and fat
- Athletes may have high BMI due to muscle mass
- Use BMI alongside other health metrics for a complete picture
- Consult a healthcare provider for personalized health advice
Questions people ask
- Is BMI accurate for everyone?
- BMI has limitations. It doesn't account for muscle mass, bone density, age, or body composition. Athletes may be classified as overweight despite being very fit. Use it as one data point among many.
- What is a healthy BMI?
- A BMI between 18.5 and 24.9 is considered normal weight. However, optimal health depends on many factors beyond BMI including diet, exercise, and genetics.