1- Stand with your back to a wall, feet flat and wearing socks.
2- Place a book between your legs.
3- Raise the book until it presses comfortably against your crotch.
4- Mark where the book touches the wall.
5- Measure from that mark down to the floor.

Height Measurement:
1-Place a book flat on top of your head while standing tall.
2- Mark the spot on the wall where the book touches it, then measure from that mark to the floor.