Reverse BMI Calculator
Enter your target BMI and height to find the exact weight you need to reach it — in both pounds and kilograms.
About the Reverse BMI Calculator
A reverse BMI calculator works backwards from the standard BMI formula — instead of calculating your BMI from your weight and height, it tells you exactly what weight corresponds to a given BMI at your height. This is useful for setting realistic weight-loss or weight-gain goals, understanding what 'healthy' BMI actually means in real pounds or kilograms for your body, and tracking progress toward a target BMI range.
Body Mass Index (BMI) is calculated as weight in kilograms divided by height in metres squared (kg/m²). To reverse this, you simply multiply your target BMI by the square of your height in metres. For example, if you are 5'9" (175.3 cm) and want a BMI of 22, the target weight is 22 × (1.753)² = 67.6 kg (149 lbs). Our calculator performs this instantly in both imperial and metric units.
BMI is a screening tool, not a diagnostic measure. It does not account for muscle mass, bone density, age, or sex-specific fat distribution. Athletes often have a 'high' BMI due to muscle rather than fat, while older adults may have a 'normal' BMI with excess body fat. Use this tool alongside body fat percentage measurements and medical advice for a complete picture of your health.
How to Use the Reverse BMI Calculator
Select your unit system (imperial or metric), enter your current height, and type the target BMI you want to achieve. The calculator instantly returns the weight in both pounds and kilograms that corresponds to that BMI at your height, along with the BMI category (underweight, normal weight, overweight, or obese).
The formula behind the calculation is straightforward: Target Weight (kg) = BMI × Height (m)². In imperial units, the equivalent formula is: Target Weight (lbs) = BMI × Height (inches)² / 703. Both are mathematically identical — only the unit conversion constant changes. Our calculator handles this automatically and displays results in both systems regardless of which unit you input.
BMI Categories and Healthy Weight Ranges
The World Health Organization classifies BMI into four main categories: Underweight (below 18.5), Normal weight (18.5–24.9), Overweight (25.0–29.9), and Obese (30.0 and above). Some organisations use additional sub-categories for severe or morbid obesity (BMI ≥ 35 or ≥ 40). For most adults, maintaining a BMI between 18.5 and 24.9 is associated with the lowest risk of weight-related chronic diseases.
You can use the reverse BMI calculator to find your healthy weight range by entering 18.5 and then 24.9 at your height — the two results give the lower and upper bounds of the 'normal weight' category. For a 5'6" (167.6 cm) person, the normal weight range corresponds to roughly 115–154 lbs (52–70 kg). This range is a more meaningful target than a single number and gives you a realistic corridor to aim for.