BMI Calculator
Use this simple tool to calculate your Body Mass Index (BMI) with either metric or imperial units.
Note: BMI is a screening tool and does not diagnose body fatness or individual health conditions.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is a quick way to estimate whether your weight is in a range generally considered healthy for your height. It uses a simple formula based on height and weight, making it one of the most widely used health screening metrics in clinics, wellness programs, and fitness tracking apps.
While BMI is not a perfect measurement, it gives a useful first signal. If your result falls outside the healthy range, it may be worth discussing with a healthcare professional and looking at additional markers such as waist circumference, blood pressure, sleep quality, activity levels, and lab results.
How to Calculate BMI
Metric Formula
BMI = weight (kg) / [height (m)]²
Example: If you weigh 70 kg and are 1.75 m tall, your BMI is 70 / (1.75 × 1.75) = 22.9.
Imperial Formula
BMI = 703 × weight (lbs) / [height (in)]²
Example: If you weigh 165 lbs and are 70 inches tall, your BMI is about 23.7.
BMI Categories for Adults
- Below 18.5: Underweight
- 18.5 to 24.9: Healthy weight
- 25.0 to 29.9: Overweight
- 30.0 and above: Obesity
These categories are commonly used for adult population-level screening. They can help identify potential health risk trends, but they should never replace personalized medical advice.
How to Use This BMI Calculator
- Select your preferred unit system (metric or imperial).
- Enter your height and weight accurately.
- Click Calculate BMI.
- Review your BMI value, category, and estimated healthy weight range.
Important Limitations of BMI
BMI is useful, but it has limits. It does not directly measure body fat percentage and cannot distinguish between fat mass and muscle mass. Because of that, some people may appear “overweight” by BMI even with excellent metabolic health.
Cases Where BMI Can Be Misleading
- Athletes with high muscle mass
- Older adults with lower muscle but higher fat percentage
- Pregnant individuals
- Children and teens (different age-based standards are needed)
What to Do If Your BMI Is High or Low
If BMI is above the healthy range
- Increase daily movement (walking, resistance training, light cardio)
- Focus meals on protein, vegetables, fiber, and minimally processed foods
- Reduce liquid calories and late-night snacking
- Track sleep and stress, since both affect weight regulation
If BMI is below the healthy range
- Increase nutrient-dense calorie intake gradually
- Add strength training to support lean body mass
- Eat consistent meals with protein, complex carbs, and healthy fats
- Consider medical evaluation to rule out underlying conditions
Final Thoughts
If your goal is better health, treat BMI as a starting point, not a final verdict. Use it together with other indicators like fitness, energy, blood markers, and lifestyle habits. Progress happens through consistent small actions—better meals, regular movement, and quality recovery.