Find a wall with high ceilings. Any wall around the house will do, as long as the ceiling is high enough so you do not hit it when you are jumping. As such, outside walls are preferable. If the wall is a dark color, that will help the process as well.
Take chalk and place it on your fingers. Make sure there is enough to rub off on the wall.
Stand flush against the wall with your arm straight up. Rub your fingers against the wall so the chalk rubs off. Use a step ladder, ruler and chalk to mark a straight line where your finger rubbed chalk onto the wall. This is the starting point for the vertical jump tester.
Apply more chalk to your fingers. Stand next to the wall. From a standing position, jump as high as you can, applying chalk on the wall from your fingers at the jump's highest point.
Take the step ladder, ruler and chalk to make another line at the new chalk mark. This is the peak of your vertical jump. While on the step ladder, use measuring tape to determine the distance between marks to find your vertical jump height.