What is the Ideal Weight at BMI 22?
This calculator returns the body weight that corresponds to a Body Mass Index (BMI) of exactly 22 for a given height. A BMI of 22 is widely used in Japan as the "standard" or "ideal" weight target, because the Japan Society for the Study of Obesity associates it with the lowest risk of lifestyle-related disease. The mathematics here is universal — it is just the BMI formula solved for weight — while the specific choice of 22 as the target reflects this Japanese standard-weight convention.
How to use it
Enter your height in centimeters and read off the weight that would place you exactly at BMI 22. Compare it with your actual weight to see how far above or below the standard reference you are. The tool fixes the BMI target at 22, so height is the only input you need.
The formula explained
BMI is defined as weight in kilograms divided by height in meters squared: \( \text{BMI} = W / h^2 \). Rearranging to solve for weight at a fixed BMI gives \( W = \text{BMI} \times h^2 \). With the target fixed at 22, the calculation becomes $$ W = 22 \times \left(\frac{\text{height}_{\text{cm}}}{100}\right)^2 $$ Note that height must first be converted from centimeters to meters by dividing by 100; plugging centimeters straight in would overstate the result by a factor of 10,000.
Worked example
For a height of 170 cm: convert to meters (1.70 m), square it (2.89), then multiply by 22 to get 63.58 kg. $$ 22 \times 1.70^2 = 22 \times 2.89 = 63.58\ \text{kg} $$ For 160 cm: \( 1.60^2 = 2.56 \), and \( 22 \times 2.56 = 56.32 \) kg.
FAQ
Why BMI 22 instead of 18.5–24.9? The 18.5–24.9 band is the "normal" range. BMI 22 sits near the middle and is the single value linked statistically to the lowest disease risk, so it is used as a point target for standard weight.
Is this an exact health target? No. It is a reference figure. Muscle mass, frame size, age, and body composition all matter, so treat the result as a guideline, not a medical prescription.
Does this apply outside Japan? The BMI math is universal. The choice of 22 as the "ideal" value follows the Japanese standard-weight convention; other guidelines may use a range instead.
