To measure your body length you need a book and a measure tape, a wall and take out your shoes. So the first step is you take the book, it has a nice 90 degrees angle, you stand straight without shoes and you drop it until you feel that it’s on your head, you turn around, you take with your finger the spot or if you don’t care, you make with a pen or pencil, a little stripe/sign and you measure your body length. My advice is do it at least two times, if it’s two times exactly the same measurement, you know that you measured both times right, if there’s a bit different you better do it the third time to know that you did it right and report to us in centimeters. You can also stand with your back straight without shoes against a wall and ask someone to hold the book above your head so you can measure the distance from the floor to the book.