The Healthy Body Calculator® will adjust if you add your current body fat percent and / or a goal body fat. However, you are underweight for height (5’11” and 128 pounds) even at 9% body fat. At your current weight, you only have 5.2 kg (11.5 pounds) of fat on your entire body!
If you are competing in a sport, your low weight will be a hindrance. Even if you are a marathon runner, your muscle mass is too low for height. Why do you want to lose down to 5% body fat?
At your current weight and height, your muscle mass and strength is diminished. I would recommend that you maintain your current body fat, increase your body weight to at least 75 kg (165 pounds) through weight lifting to increase muscle mass. Are you comfortable with this goal?
