Stand barefoot against a flat wall on a hard floor
Remove shoes, hat, and bulky hair accessories
Keep your heels, back, and head touching the wall
Look straight ahead with your chin level
Place a flat object like a book on top of your head
Mark the wall where the bottom of the object touches
Measure from the floor to the mark with a tape measure or ruler
Measure at the same time of day for consistency
Have someone help you for more accuracy
Record the measurement in feet and inches or centimeters