Get a book, a hand mirror and a pencil.
Take off your shoes and anything you wear on your head.
Look for a level surface to stand on with a smooth wall behind you.
Stand in front of the wall with your feet together.
Balance the book on your head and press it against the wall. Use the mirror to check that it is in a horizontal position and well centered. Mark the position of the top of your head on the wall with pencil.
Once the mark is made, step away and use a measuring tape to measure the distance from the ground to the mark you just made with pencil.
